The size of a greenhouse can be determined primarily by the quantity of plants you plan to grow during the period of cold weather when additional heat and protection from frost is required. Plants that prefer warmer climates can continue to grow inside the greenhouse to produce flowers, fruits, or vegetables through cold and warm seasons. Plants, requiring shade during both cold and warm weather, can be protected from direct sun with a shade cloth. Size also will be influenced by the amount of space and money you have available.
The square footage required can be determined by laying out a floor plan that includes growing areas, walkways, and work and storage spaces not provided for in other structures. Enough space should be provided to prevent plants from touching greenhouse walls during freezing weather and to allow adequate air circulation. Plants should be reachable from walkways or from between benches and beds to allow for regular watering, fertilizing, and insect and disease control.
Walkways must accommodate the movement of workers, customers, equipment, plants, and vegetables in and out of the greenhouse. However, you want to minimize your walk, work, and storage areas as much as possible, because only the growing areas provide income or plants and vegetables for your own use.
If you are a commercial grower your greenhouse will need to accommodate trucks backing into (or at least close to) the greenhouse to load and unload. If this is the case make sure the greenhouse doors are large enough to accommodate them.
If money is tight, you can make the permanent greenhouse smaller by using less expensive temporary structures to raise early and late vegetables. Bedding plants can also be moved outside early to harden off, using temporary covers to protect them when frost is predicted.
Double and triple uses of greenhouse space allow for increased production per square foot. A simple wooden or metal frame can be built over a supply-storage area, creating more room for flats of plants. Temporary benches, filled with plants, can be set between rows of transplanted vegetables and moved as space needs change. Lettuce, spinach, radishes and other quick maturing crops can be planted early between tomato and pepper plants and harvested before later crops grow large enough to block the light.
Greenhouse rafters should be high enough to hang baskets above the heads of workers and customers, especially in walkways, yet low enough to water and fertilize regularly. They will need to be spaced far enough apart to grow without crowding and to allow light penetration to plants below.
How Temperature Control Helps Your Greenhouse Plants
Photo by www.zanda. photography on Unsplash
If you’re an enthusiastic gardener, it’s amazing how you lose track of time while tending to your garden, right? It’s such a satisfying feeling seeing your plants blossom and grow. But did you know you can do even more for your plants when controlling the temperatures in your greenhouse?
Identify Your Specific Greenhouse Needs
Not all greenhouses are identical. Each greenhouse has a unique design and structure. If you’re a greenhouse manager, your first task is to ascertain the cooling and heating systems required for your specific greenhouse. If you’re simply an enthusiast that turned your backyard shack into a greenhouse, the same applies.
Testing different cooling solutions is essential for your specific greenhouse to ensure you achieve the ideal temperature for optimal growth. Look at it as a trial and error exercise.
Do It On A Budget
You don’t have to go to the extreme with expensive chillers and heating systems to get your greenhouse functioning efficiently. Keep it simple with low-cost cooling methods such as shade cloths and circulating fans.
Using Shade Cloths
Something as simple and inexpensive as a shade cloth or curtain can lower the temperature inside the greenhouse significantly. Use a smart cooling method for effective temperature control. The only drawback of using shade cloths is you’ll have to consider light will be blocked out. Some plants in the greenhouse need light, so be careful of how much of this method you implement.
Ventilation Is Key
Accuserv air conditioning and repair services know all too well the benefits of ventilation; the same is true for greenhouse managers and owners. They know there are several ways to ventilate a greenhouse. You can either use an open roof or sidewalls that open up to allow air to flow to lower temperatures in your greenhouse.
If you decide to use the open roof or sidewall method, to maximize the cooling effect, make a note of the direction of the wind.
Keep The Air Flowing
If you pride yourself on being a respectable greenhouse manager, then you should know circulating fans are useful tools used to control temperatures. These fans allow the air to flow optimally inside the greenhouse.
The circulating fans work well to keep temperatures consistent. They push out warm air and hold cold air down to make sure the area doesn’t overheat.
Continue to enjoy your time in your greenhouse when using these easy tips for controlling temperatures more effectively. The methods listed are cost-effective and straightforward so that you can implement them immediately. Let your fingers do the pruning and enjoy better-controlled temperatures for your green buds.
We want to hear if you have any other tips to share on controlling temperatures in a greenhouse. Leave a comment below and help others in your position.
The 6 Most Common Greenhouse Crops
Are you living in or moving to Liberty Hill? While the area is great for luxury activities such as camping and hiking thanks to its natural beauty, you can also utilize the vast landscape and ideal climate with greenhouse farming.
We’ve taken the liberty to highlight some of the most common greenhouse crops you can plant that are highly profitable, so you can turn your hobby into a lucrative business.
Things to Consider When Picking Crops
Before deciding on which crops are the best for planting in a greenhouse farm, there are a few factors you to consider.
Single or Multiple Crops?
Do you want to grow single or multiple crops? Experts strongly recommend that you stick to a single crop so you can concentrate all your time, effort and resources to ensure it grows healthy and lush. This is because taking on different kinds of crops at the same time will require different and specialized needs with regards to:
Are You a Beginner or Experienced Farmer?
If you’re new to the greenhouse farming business – or farming altogether – it’s advisable to start with a crop that’s easier to grow and monitor until harvest time.
How Much Space do You Have?
You’ll also need to determine exactly how much space you have in your backyard for a greenhouse. This is important for estimating the costs involved with a crop you are considering.
Types of Crops to Choose
Fruits and vegetables are the most common type of crop that can thrive in greenhouse environments. We list a few examples below.
Tomatoes are among the common crops that many greenhouse farmers prefer planting because of how many you can grow. They’re also very profitable, with almost every household using tomatoes in some fashion in their usual diet.
Lettuce is another favorite crop among greenhouse enthusiasts. It can be profitable, but it’s also relatively easy to grow for beginners or casual farmers. There are also many different kinds of lettuce that you can grow.
Cucumbers are a highly profitable vegetable to grow because of how versatile they are in catering and cooking. They are not as popular as tomatoes or lettuce, because they are not as easy to keep fresh after harvesting. Nonetheless, if you grow organic cucumbers they can fetch high prices.
Have a few popular varieties and colors, but mainly red, yellow and green. We’ll quickly point out that peppers aren’t the easiest greenhouse crops to grow but they’re still very profitable due to their use in popular cooking dishes like stir fry.
Here is yet another vegetable that’s best suited for greenhouse environment. Beginners will appreciate how fast it grows, but its growth depends on the environmental and climate conditions.
Now, from the above mentioned vegetables, which one will you grow in your greenhouse once you move into one of the new homes in Liberty Hill?
Greenhouse 101: 3 Useful Tips Every Beginner Should Know
Invest in the correct seed starting supplies for your greenhouse.
If you’re looking for a gratifying hobby, cultivating your own plants in a greenhouse may be right for you. To ensure your success as a beginner, checkout the following tips:
Before you get a start plotting out your growing schedule, buy the correct materials. For starters, purchase the following basics:
- Seeds or starters
Seeds are the most cost-efficient option for newbies. You may also avail of starters that are sold at plant nurseries.
Make sure that you’re choosing durable and disease-resistant plants. Cultivate plants that are easy to care for and won’t die easily. Here are a few examples:
You need suitable containers for growing your plants. Check that the containers you choose are deep enough to contain the plant’s root system. Otherwise, your plants won’t thrive. Additionally, make sure you sterilize your containers properly before using them.
- Sterile soil
Do not plant on unsterilized soil as it may contain parasites and bacteria that will harm your seedlings. If you still prefer to use soil that’s collected straight from the ground or used before, sterilize it. The best option, however, is to invest your money and buy fresh sterile soil.
You’ll need fertilizer to boost the growth of your plants. Note that most of the commercial soil being sold in stores already have nutrients in them to feed plants for approximately three weeks. So, be careful not to overuse fertilizer when you’re beginning. To be safe, give fertilizer a little bit at a time. You may start by giving a diluted fertilizer solution and then slowly strengthen the solution per week.
- Wear appropriate clothes and footwear for gardening.
Make sure to choose clothes that are fit for gardening chores. Interestingly, you have to avoid wearing bright-colored outfits because these attract insects that will follow you inside your greenhouse.
Make sure you wear gardening boots that properly protect your feet while you work in your greenhouse. Check out online sites such as workboothub.com for a list of the best gardening boots you can choose from.
- Install an adequate lighting system inside your greenhouse.
In late spring up to the summer months, sufficient light will reach your plants in the greenhouse. If you want to plant year-round, you need to invest in a supplementary lighting system so that you can continue to cultivate healthy plants all throughout autumn and winter.
When you’re starting out and have a small crop, a regular fluorescent strip hung 3 to 7 inches over your plants will be enough. Once you have a bigger area, upgrade your lighting system to LED grow lights. These are quite the popular choice as they conserve energy while lighting up larger areas.
Follow these basic tips and continue to research the best practices for making your greenhouse thrive. The effort you put into your very own greenhouse will definitely be worth it!
Deep Clean Your Greenhouse
Plants love the warm, humid, cozy protection of a greenhouse. The problem is that pests and diseases do also. We have to get rid of them to keep our precious plants healthy. A deep cleaning does not only that but also improves the overall aesthetics of the greenhouse. It’s a job—there’s no doubt about that, but it helps if you break the chore down into the simple steps below rather than careen from one task to another and back again. Luckily enough, the folks at HousewaresInsider.com have compiled a short list of handy steps to follow.
That would be everything: plants, soil, weeds, debris of any kind, containers, equipment, clutter that somehow made its way into your greenhouse. There can be no place for any creepy crawlers or pathogens to hide
“Shop vac” or sweep down walls, internal structures and peripherals, such as tables, benches and containers. Start at the top where dangerous organisms lurk in such places as rafters and window ledges. Clean the floor of the assorted debris that gathers there: soil, organic matter, weeds, broken pottery shards.
Now scrub or power wash everything. If you use soap, be sure that it is a gentle, natural soap that leaves no residue. Otherwise, rinse very thoroughly to remove any residue. Hydrogen peroxide-based products are both user- and environment-friendly. Garden disinfectants work fine, as do specialty greenhouse cleaners combining sulfuric acid and wetting agents. Whatever you use, it is of utmost importance that you follow manufacturer’s directions.
Wood tables and benches and any concrete areas (and, actually, any textured surface) need special attention. They are favorite places for root rot diseases, algae and insects to breed. If you are going to reuse containers, clean thoroughly to remove all soil and debris even if there has been no problems with disease.
Let the Sun In
Plants need all the sunlight they can get. Keeping the glass clean is a “must do.” Begin by lifting of any moss or algae with any utensil that won’t scratch the glass, but you really can’t beat those plastic plant labels that can get into every crack and crevice. Wash the glass with a firm brush and a mild all-purpose liquid cleaner that doesn’t need rinsing. Open the windows to speed up drying and give the hinges a quick fix of WD-40 while you’re at it.
Clean Gutters and Water Butts
To clean the gutters, put on rubber gloves and scoop out the accumulated debris. Use a wire coat hanger to “ream out” the top of fall pipes. Then use the hose to sluice away the remaining dirt.
To clean water butts, tip over to drain out any standing water. Scrub out the inside with a coarse brush and rinse with clean water.
Are you ready to resolve to keep the greenhouse clean? Not only to save yourself work but also because it’s easier and less expensive to prevent insect infestation and diseases than to deal with them once they have settled in. Some routine preventive measures:
- Sanitize tools, containers and equipment immediately after use,
- Wash your hands prior to contact with plants, soil or equipment,
- Wash your gardening gloves after use,
- Keep a pair of shoes or boots to be used only in the greenhouse,
- Keep plants (and the floor) free of weeds,
- Toss diseased plants immediately, and (believe it or not)
- Avoid bright-colored clothing, especially yellow or blue—you’ll attract insects who will “stalk” you right into the greenhouse.
Preventing Pest Infestations in a Greenhouse
The spring season brings new beginnings for plant growth. The landscape becomes green again and multitudes of colors and fragrances fill the air as flowers break through the ground’s surface. The new life brought on by spring is rejuvenating for horticulturists. It is not just plants and flowers that “come alive” during this time of year. Just as new plant life emerges all around us in spring, new life for pest insects is also resurrected. As temperatures rise and the summer months approach, more and more insects leave dormancy and begin new life cycles. This is why it is so important for greenhouse gardeners to be aware of and take counter measures against pest insects during the spring and early summer seasons. In many cases, a few simple preventative steps can reduce the likelihood of a devastating pest insect attack.
Sanitation is the number one defense against pest insect infestations. Keeping the greenhouse and the plants clean and tidy can do wonders in preventing pest insects and pathogens. Periodically wiping down the surface of the greenhouse and removing dead or dying vegetation will greatly reduce the possibility of pest insects. Plants should be closely monitored for pest insects on a weekly basis (at the very least).
It is a good idea to set up a quarantine area in the greenhouse. Whenever a new plant is purchased or gifted, it should be quarantined immediately for a week or two to ensure it does not harbor pest insects. After the quarantine period is over and the plant has received a clean bill of health, it may join the other plants in the greenhouse. Bringing new plants into a greenhouse is the most common way a greenhouse gardener will introduce pest insects into his or her own garden. If pest insects are observed on any new plant, it should be thoroughly treated before being introduced to the other plants in the greenhouse.
Monitoring for Pests
As previously mentioned, it is important for greenhouse growers to monitor their gardens for any signs of pest insects. Yellow sticky traps are great tools for monitoring a greenhouse. Yellow sticky traps are similar to fly paper in that they “catch” flying insects in a glue-like substance. By closely examining the yellow sticky trap, a gardener can see if and what types of pest insects are present in the garden. Yellow sticky traps allow a horticulturist to identify potential problems before they get out of hand.
Identifying the Pest Insect
Identifying the pest insect early and accurately is vital to stopping a few pest insects from becoming an infestation. When monitoring the plants, there are some tell-tale signs that will indicate which pest insect a gardener may be dealing with.
The first sign of a spider mite problem usually shows up in the form of yellow speckling on the surface of the leaves, which is caused by the insects sucking nutrients from the underside of the plant leaves. The speckling from spider mite damage will resemble light yellow spray paint misted on the leaves. Closer examination of the bottom of the leaves will reveal clusters of very tiny red mites and their eggs. A magnifying glass may be necessary to see them. In more extreme infestations, webbing may be found in-between or on the tips of branches and leaves. This webbing looks very much like a spider web and is how these nasty bugs received their name. Spider mites are difficult to get rid of and require a miticide for treatment.
The first sign of mealybugs is normally cotton-like, fluffy masses found in the crotches or joints of the plant, typically near young tender growth. These tiny “cotton balls” are actually clusters of the slow moving mealybugs. These bugs can reproduce and lay eggs every seven days, so they should be treated immediately to reduce any possible contaminations. It’s difficult to kill the eggs, often in the soil, so it’s important to treat for live mealy bugs every five to seven days for three to four weeks to terminate all adults before they become mature enough to lay eggs.
The first sign of a fungus gnat problem is typically the small, mosquito-like, black or gray insects that fly around aimlessly. They are most prevalent right after a watering or when the soil is disturbed. Fungus gnat larvae look like tiny, light-colored worms that wiggle around in the top layer of soil. They can sometimes be seen “dancing” in standing water after a feeding.
The first sign of a thrip issue is usually “shiny streaks” that show up on the surface of the leaves. The shiny trails are actually the areas of the leaf where the thrip larvae have been feeding. Gardeners may also notice tiny black specs on the leaf surface; this is actually the larvae’s fecal matter. To the naked eye, thrip larvae resemble fast moving grains of rice. The larvae can be many different colors, but are usually yellowish-green.
The first sign of scale is usually a protective covering or bumps on the stems and stalks of the plants. The females lay eggs underneath the protective covering, which will hatch in one to three weeks. The newly hatched nymphs leave the protective covering as tiny white specs and move around the plant to feed. Nymphs insert their piercing mouthparts into the plant and begin to feed, gradually developing their own protective covering as they turn into immobile adults. Scale do not pupate and may have several overlapping generations in one season. A scale infestation is difficult to eliminate and requires a systemic insecticide.
Treatment and Control
Early detection and treatment diligence are the keys to eradicating pest insects. A gardener can start treatment with an organic or all-natural insecticide that is designed for the particular pest insect he or she is battling. Yellow sticky traps are effective in capturing most flying insects, such as fungus gnats and white flies. Denatured alcohol is highly effective as a combatant against mealy bugs and scale by wiping it on the infected areas with a cotton swab or small paint brush. Pyrethrum is an organic derivative of the chrysanthemum plant and is extremely effective against many greenhouse pest insects. Pyrethrum is the primary ingredient in several commercial spray products commonly available at most garden centers. In some cases, a pest insect (scale and mites), cannot be controlled with an organic or all-natural approach.
When this occurs, the gardener may need to implement a systemic chemical control. Systemic pesticides, such as Orthene, are effective against pest insects because they enter the plant’s tissue and kill the bugs as they feed on the plant tissue. Regardless of the treatment program, horticulturists should always use caution and be sure to read the manufacturer’s directions for application.
For more information visit ArcadiaGlasshouse.com
Hardening Off Your Seedlings
When seedlings are started indoors or in a greenhouse, they become acclimated to an environment that is much less severe than the outdoors. It is sometimes hard for novice gardeners to comprehend that direct sunlight, strong winds, and cooler nighttime temperatures are simply too much for many seedlings or small plants to handle. The process of hardening off is meant to reduce the shock of transitioning from a sheltered environment to outdoor conditions. The three biggest factors affecting a plant’s transition from an indoor environment to an outdoor environment are direct sunlight, wind and temperature.
Many gardeners do not realize how much more intense the sun is than an artificial light source. Even plants grown under high intensity discharge lighting will have a hard time transitioning into the intensity of direct sunlight. Tender seedlings and young plants grown indoors on a window sill or under a grow light must be gradually transitioned into direct sunlight. Start by placing the tender seedlings in a shaded area. After a couple of days in the shade, the seedlings can be introduced to direct sunlight. Remember, gradual increases are the key to success in the hardening off process. Each day a grower can increase the amount of time the seedlings receive direct sunlight. Depending on the particular plant variety, the grower can usually increase the duration of time in direct sunlight by 1-2 hours per day. Typically, seedlings should be acclimated to the direct sunlight in about a week’s time.
Many seedlings and young plants get accustomed to a high humidity environment. When placed outdoors, the wind and dry air can quickly dry out the medium and/or the seedlings themselves. If there is a strong wind present when a gardener is hardening off his or her plants, it is a good idea to create some sort of wind block for the seedlings. Cold frames or mini hoop houses are valuable tools for the hardening off process and can offer additional wind protection for transitioning plants.
Many gardeners start the hardening off process when the night temperatures are still too cold for the seedlings. It may be necessary to bring the seedlings back inside each evening until the temperature at night increases or the plants become acclimated to the colder temperatures. Cold frames or other temporary structures that offer cover can be used to protect the seedlings from the lower nighttime temperatures.
A cold frame is an unheated greenhouse, usually used to temporarily house plants during the spring or early summer. Cold frames are a valuable tool for hardening off seedlings and young plants before planting them in the garden. A cold frame works great for sheltering young plants while allowing them a “taste” of life outdoors. The most common type of cold frame used by home hobbyists is a box-style cold frame.
A box-style cold frame is nothing more than a bottomless box with an angled, transparent top. Box-style cold frames come in different styles and sizes and can be purchased or built from various materials. Some cold frames are as basic as a box made of cinderblocks with an old sheet of glass on top, while other cold frames are more advanced composite structures complete with a thermostatic auto-opener. Manufactured cold frames built from aluminum and polycarbonate offer the advantage of longevity and are backed by a manufacturer’s warranty.
Seedlings and young plants that are hardened off properly will transition more seamlessly into outdoor conditions. It only takes one bad experience for a horticulturist to realize how important the hardening off process really is. After all, the last thing a gardener wants is to have to replant all of his or her seeds and play catch-up for the rest of the growing season. Hardening off is most effective when done in incremental steps. When in doubt, take the slow route. In other words, rushing the hardening off process can be extremely counterproductive. A hobbyist who properly hardens off his or her plants will not only have healthier plants and a smoother transition to the outdoors, but will also have a more enjoyable experience in the garden.
For more information, please visit ArcadiaGlasshouse.com.
Starting Seeds Indoors or in a Greenhouse
Spring is approaching and, for gardeners, this means a fresh start to another growing season. Many horticulturists choose to start seeds indoors or in a greenhouse in order to have plants ready to grow in the upcoming season. There are a few considerations every horticulturist should make before starting his or her seeds. Following a few simple guidelines will help make the seed starting experience both enjoyable and effective.
As with most things in life, timing is everything. It is important for a horticulturist to take into consideration his or her geographical location’s average last frost date. A quick search on the internet or call to a local greenhouse can help a gardener determine in which zone he or she lives. Here are the zones and their corresponding average last frost date:
Zone 1 – June 15th
Zone 2 – May 15th
Zone 3 – May 15th
Zone 4 – May 15th
Zone 5 – April 15th
Zone 6 – April 15th
Zone 7 – April 15th
Zone 8 – March 15th
Zone 9 – February 15th
A good rule of thumb for starting seeds is to begin the germination process 6-8 weeks before your zone’s average last frost date. It is also important to consider the particular plant varieties being grown. For example, many ornamental flowers can be started earlier, around 8-10 weeks before the average last frost date. Cold sensitive plants that require warmer temperatures to grow properly, like tomatoes, basil and peppers, should be started a little later, around 6-8 weeks before the average last frost date.
Grow Medium and Planting Containers
It is very important to make or buy a seed starting medium that is specific for starting seeds. Regular potting soil is too heavy and potent for most seeds. Plug trays or peat pellets are great for starting seeds, but will require transplanting after the seedling has developed its second set of true leaves. I personally prefer using small plastic cups with small holes poked in the bottom for drainage. These small cups are big enough for the plant to establish a heathy root structure and can usually be used until the plant is placed outdoors or into its finishing planting container. Filling a tray with medium and planting multiple seeds should be avoided, if possible. Not only does this create a less than desirable root structure, it also makes it difficult to separate the seedlings without damaging them.
Some seeds are very small and are extremely difficult to plant individually. One technique is to use the eraser end of a pencil to pick up and gently bury the seed into the medium.
Temperature and Humidity
Proper temperature and humidity are necessary for healthy seedling development. A heat mat is a great way to supply heat to the seedling bed, which helps initiate the germination process. Not only do heat mats provide the warmth necessary for germination, they also help keep the temperature more consistent around the seedlings. All plants, especially seedlings, thrive on consistency. Although not completely necessary, many gardeners like to use a humidity dome on their seedling trays. Generally speaking, seedlings prefer a higher humidity than the ambient air. Humidity domes are an inexpensive and simple way to maintain higher humidity for the seedlings. Humidity domes, like heat mats, will also help maintain consistent atmospheric conditions.
If they are being grown indoors, seedlings should be placed as close to a window as possible. If they are being grown in a greenhouse, try to position the seedlings in an area that receives the most light. Many growers use an artificial light source for starting seeds indoors or in a greenhouse. If you have ever experienced leggy, stretched stems on seedlings, you have seen the results of inadequate lighting. An artificial light source above the seedlings will keep them compact and healthy. There are many different artificial light sources that can be used for seedlings, but T5 fluorescents are highly effective and relatively inexpensive. A light for starting seeds is a valuable tool and is well worth the investment.
Starting seeds in a greenhouse or indoors is a fun and easy way to get a head start on the growing season. Hobbyists who start their seeds at the right time, while also supplying the proper medium, atmospheric conditions and lighting will not only have higher germination success, but will also have many healthy seedlings ready to take on the upcoming growing season.
For more information visit ArcadiaGlasshouse.com
Sanitizing the Greenhouse and Overwintering Plants
As the cold weather approaches, greenhouse growers should begin preparing their greenhouses for the winter. Before bringing in the plants from outside, a good sanitizing of the greenhouse and the plants themselves is recommended. This can be viewed as a yearly maintenance and preventative procedure which can greatly reduce the likelihood of problems during the winter months. A good cleaning combined with proper placement of the plants in the greenhouse equates to a smoother transition into next year’s growing season.
Sanitizing the Greenhouse
Before moving plants into the greenhouse for overwintering, it is a good idea to thoroughly clean the greenhouse. Start by removing any plants that are currently in the greenhouse. After the greenhouse is empty, hose down the entire greenhouse with soapy water. In most cases, soapy water is enough to prevent algae build up on the glaze or framing of the greenhouse. If algae have already built up, a good pressure wash can easily rectify the problem. It is very important for owners of polycarbonate greenhouses to avoid using window cleaners of any kind. Window cleaners can actually damage the polycarbonate panels and make them less transparent.
After using soapy water and/or the pressure washer, it is a good idea to further sanitize the greenhouses with a sterilizing/sanitizing agent. A diluted bleach solution is one sanitizing agent commonly used by greenhouse horticulturists. However, there are two distinct disadvantages to using a bleach solution. First, the odor and fumes created by bleach can be overwhelming, especially when used in a contained area like a greenhouse. Second, a diluted bleach solution works fine for sanitizing the greenhouse itself, but should not be used on the plants that will be coming into the greenhouse from outside. Even a diluted bleach solution would be harmful to the plants. Molds and pathogens often enter the greenhouse by hitching a ride on a plant or in the soil of a plant brought in from outside.
A good solution to this is a cleaning agent called Physan 20. Physan 20 is an algaecide, fungicide, bactericide, and virucide. In other words, Physan 20 helps fight algae, fungi, bacteria, and viruses. After washing the greenhouse with soapy water, an application of Physan 20 will kill any remaining fungi, algae, bacteria, or viruses. Physan 20 is virtually odorless which makes it much easier to work with than a diluted bleach solution. Perhaps the largest advantage of Physan 20 is its ability to be used directly on ornamental plants and their soil. Physan 20 can be used as a soil drench to kill any pathogenic fungi, bacteria, algae, or viruses lurking in the soil of plants kept outdoors. Physan 20 comes in a concentrate form and must be diluted before use. Horticulturists should pay close attention to the manufacturer’s recommended dilution rates for the various uses of the product. In other words, the recommended concentration for cleaning the greenhouse material will differ from the concentration for a soil drench.
Preparing the Plants for Overwintering
Before bringing outside plants into the greenhouse for the winter, a gardener should take a few steps to make the transition smoother. Start with cleaning the plants themselves by removing any dead or dying leaves from the plant and soil container. Examine the plants closely for pest insects. Any pest insect issues should be treated before bringing those plants into the greenhouse. If possible, time your watering so that the plants can receive a watering with the Physan 20 mixture right before entering the greenhouse for the winter. As previously mentioned, this will kill any fungi, algae, bacteria, or viruses that may be contained in the soil.
Plant placement is another important factor to consider when overwintering. Some plants are more sensitive to cold than others. The plants that will better handle cold conditions should be placed along the perimeter of the greenhouse and those more sensitive to the cold should be place closer to the center. If the plan is to grow orchids or food crops, the greenhouse will need to be heated by some sort of heating device in order to keep the ambient air temperature warm enough for flower/fruit production.
Sanitizing the greenhouse is an important preventive measure that can be the difference between a smooth transition and an utter catastrophe come spring. Cleaning and sanitizing the plants before they enter the greenhouse is a vital step to keep the plants healthy and happy all winter long. Proper plant placement is another crucial factor contributing to the heath of the plants. When planning the layout of the greenhouse for winter, do not forget to leave some space for next spring’s seedings. After all, winter will be over before you know it and the next chapter of your garden will soon begin.
For more information visit ArcadiaGlasshouse.com.
Hydroponic Systems in a Greenhouse
Accessibility to information, due mainly to the internet, has many home greenhouse hobbyists experimenting with hydroponic systems in a greenhouse. Hydroponic gardening is gardening without the use of soil. In other words, any type of growing system that bypasses the microbes in the soil and directly feeds the plants with nutrients can be considered hydroponics. There are many different hydroponic growing systems and each has its own advantages and disadvantages. A closer look at some of the systems commonly used by home hobbyists will give a grower a bit of insight into the fascinating world of hydroponic gardening and some inspiration to start experimenting.
Deep Water Culture
Deep water culture is perhaps the easiest hydroponic system to set up. A five gallon bucket or tupperware container can be converted into a deep water culture system with just a few parts from the hardware store. In a deep water culture system, the plant is held in place by a small amount of inert medium (usually gravel or clay pebbles). However, the vast majority of the plant’s roots do not grow in the medium, but, rather, dangle down into the container where they are submersed in the nutrient solution. These systems are great because they are easy to build and can produce quick, vigorous growth. The biggest drawback of deep water culture systems is how susceptible they are to temperature changes. Since the roots are submersed in the solution, the temperature of that solution will greatly affect the way the plant’s roots can receive oxygen. When temperatures are too warm, the plant’s roots will not receive the oxygen they require and they will become susceptible to pathogens. For this reason, deep water culture should only be used by greenhouse growers in cooler climates or growers who have invested in cooling devices, such as water chillers or air conditioners. Without a cooling device, a grower may have a difficult time keeping the system’s temperature in the desired range (65-75 degrees F).
In a top-drip hydroponic system, the nutrient solution is delivered to each plant via a drip stake or drip line emitter. The individual plant modules will vary from system to system, but, generally, top-drip gardeners use standard potting containers. The medium for the containers can be any sort of inert medium or even soil if the grower wishes to have a more hybrid hydroponic/soil system. Top-drip systems can be set up as a recirculating system or a run-to-waste system. Recirculating top-drip systems will need a reservoir for holding the nutrient solution and the reservoir will need to be aerated. A timer is needed to trigger the pump for feeding intervals. The duration will fluctuate depending on the crop being grown and the particular stage of growth. Although top-drip systems are a little more expensive to start up than a deep water culture system, they fare much better at higher temperatures. Top-drip systems are also the preferred hydroponic system of commercial tomato growers.
Flood and Drain
A flood and drain system uses a table or trough which is flooded with nutrient solution for a given period of time and then drained. Traditional flood and drain systems use gravity to return the nutrient solution to the reservoir. In other words, once the pump that pushes water to fill the flood table is deactivated, the water drains back to the reservoir. Typically, containers filled with a medium, such as hydroton, stone wool, coco coir, or another soilless mix, are placed in the flood tables; however, the medium can also be placed directly in the table or trough. Flood and drain systems work well for hobbyists looking to experiment with hydroponics and/or beginner gardeners because they are easy to build and can accept a wide range of media. Like top-drip systems, flood and drain systems can offer a hybrid hydroponic/soil system to growers who are not ready to give up soil gardening completely, but still want to gain some of the benefits hydroponic gardening has to offer.
The previously mentioned hydroponic systems are commonly used by beginner hydroponic growers or hobbyists looking to do a little experimenting with hydroponics. Other systems, like aeroponics, nutrient film technique, and current culture, can also be used, but are typically reserved for growers with more hydroponics experience. That being said, remember that experimentation with hydroponic systems is a fun and exciting way to differentiate your greenhouse from others. There is no shame in trying out a new hydroponic system or trying to develop your own system for your particular greenhouse. Like other styles of gardening, hydroponic systems offer a lifetime of learning to anyone willing to give it a try.
For more information visit ArcadiaGlasshouse.com
Arcadia Glasshouse Video Will Make Anyone Want to Get a Greenhouse
If this video from Arcadia Glasshouse doesn’t make you want to get a greenhouse nothing will. Enjoy!
Organic Gardening in the Greenhouse
There is a lot of buzz surrounding sustainable and organic gardening. An increasing amount of people are realizing that the health benefits of eating organic foods extend not only to their own health but also contribute to the health of the entire planet. Conventional farming’s use of chemical pesticides, chemical herbicides, and genetically modified organisms (GMOs) has many people concerned about the safety of the food found in grocery stores. This worry has more and more people wanting to control their food supply. Perhaps the best way to do this is to start an organic vegetable garden. In fact, many people are beginning to grow their own organic food, not necessarily to save money, but to ensure the quality of the food they consume.
Growing Organic in the Greenhouse
To grow organically means to grow plants without the use of chemical fertilizers or chemical pesticides. Simply put, what we call organic gardening today was what our grandparents just called gardening. Compost bins or piles are a great way to repurpose unwanted food scraps into usable fertilizer for an organic garden. There are also many prepackaged soils, fertilizers, and pesticides that carry the organic certification. Whether you build your own rich organic soil with compost or purchase prepackaged organic soil, organic horticulture in a greenhouse offers many distinct advantages. First and foremost, with the use of supplemental heat, greenhouse hobbyists have the unique opportunity to grow organic produce year round. Read our blog, Grow All Year Round with Artificial Heat.
Greenhouse growers with both supplemental lighting and supplemental heating have the ability to grow just about anything throughout the entire year. This means you can continuously supply or supplement your diet with homegrown organic produce. In fact, if staggered correctly, it is possible to grow many of the most popular vegetables throughout the entire year, including in the winter. Another huge advantage of organic gardening in a greenhouse is the heightened control that greenhouse horticulture offers. From environmental factors to pest and pathogen prevention, growing in a greenhouse gives more power to the horticulturist. In fact, greenhouse growers are not only able to extent the growing season into the fall/winter but can also get vegetables earlier in the spring and early summer. By growing all or a good portion of your own vegetables in a greenhouse, you can be certain of the quality of your produce and take control of your health.
Getting started with organic horticulture is as easy as purchasing certified organic seeds and potting soils or building your own organic soil from raw ingredients. There are many organic fertilizers, pesticides, and herbicides available which makes converting to organic very easy and convenient. Just about any style of gardening can easily be converted to organic growing. Many greenhouse growers prefer benches with containers while others prefer raised beds. Since you can successfully grow organic produce in either potting containers or raised beds, the decision comes down to the personal preference of the horticulturist or the crops themselves (some plants do better in raised beds than containers and vice versa).
Growing organic produce in a greenhouse is a fun and healthy hobby. There are few things as rewarding as producing your own fresh, organic herbs and/or vegetables. Growing organic produce in a greenhouse is an ongoing educational hobby that revitalizes and refreshes horticulturists year after year. After all, organic gardening in a greenhouse is a hobby that can be enjoyed for a lifetime.
For more information, please visit: ArcadiaGlassHouse.com.
Sizing Your Greenhouse for Optimum Utilization of Space
Prior to setting up a greenhouse it is important to consider how the space within the greenhouse will be utilized. Unfortunately, many gardeners do not think about how they are going to use the space before they set up or purchase a greenhouse. This can lead to frustration and an unsatisfying greenhouse experience. However, with a little forethought, you can get the appropriately sized greenhouse for your particular needs and desires. When thinking about the utilization of space, it is important to examine the available widths of the greenhouse and how it will affect the greenhouse’s layout.
Greenhouses come in all lengths and widths. When contemplating the layout or floor plan of a greenhouse, a gardener should be most concerned with the width of the greenhouse because, in most cases, that is what will determine the dimensions of the benches and aisles. Hobby greenhouses are most commonly 8 or 10 feet wide but can also range from 12 – 20 foot widths. Most commercial or production greenhouses are usually wider and range from 20 feet and up. As previously mentioned, the width is important because it will determine the size of the benches that can be used. Benches are extremely popular for greenhouse gardeners and are used by most hobbyists. By examining the width of the greenhouse, a horticulturist can determine what kind of bench and aisle spacing he or she can have.
8 Foot Width
Many “hobby” greenhouses are available in 8 foot widths. Unfortunately, the 8 foot measurement is a representation of the outside dimensions of the greenhouse. In other words, this measurement does not take the frame into consideration and, therefore, the actual width on the inside will not be a full 8 feet. Greenhouses with 8 foot widths typically have 2 foot wide benches on either side of a 3 foot wide aisle. Although this may be big enough for some hobbyists, many horticulturists will quickly fill up the bench space and wish they had more room.
10 Foot Width
Greenhouses with a width of 10 feet are very popular among hobbyists because they instantly give 30% more bench space than an 8 foot wide greenhouse. A typical set up in a 10 foot wide greenhouse is to have 3 foot benches on either side of a 3 foot wide aisle. A 3 foot bench is the perfect size because it provides sufficient space for plants while not being so deep that the horticulturist can’t reach the plants. All in all, a 10 foot wide greenhouse is a nice, comfortable width for hobbyists.
12 – 20 Foot Widths
Greenhouses that range from 12 – 20 feet wide are a good choice for horticulturists who want to grow on more than just benches. Growers who want to incorporate raised beds or who have a collection of tropical plants which need additional head space will find a greenhouse in this width range more suitable to their needs. Greenhouses of this width are also nice for hobbyists who want to add a seating area, water feature, or some other unique addition to their garden spaces. All of these greenhouse extras will take up space so always be sure to plan your greenhouse layout accordingly.
20+ Foot Width
Larger width greenhouses (20+ feet wide) are mainly reserved for educational or commercial applications. These wide greenhouses can have two 3 foot aisles with 3 foot benches on the outer sides and a 6 – 8 foot bench in the center. When optimizing space for production, these greenhouses are the ticket.
Before purchasing or building a greenhouse, make sure you take the time to think about the space within and how that space will be utilized. In most cases, the grower’s intended application will determine the width of the greenhouse. A good greenhouse manufacturer will help you determine the most appropriate width for your application and help guide you to optimize the space within.
For more information visit ArcadiaGlasshouse.com
Using a Greenhouse to Start Flower and Vegetable Plants in March
March is a good month to begin plants for your flower and vegetable gardens. Listed below are some of the more common flower and vegetable plants that can be started in March. They will be ready to transplant outside in April and May. Varieties can be easily started in 1204 packs or 3″– 4″ pots. Plants in packs should be thinned to one plant per cell. The larger you want your transplants to grow, the bigger the cell or pot should be. If your germination space is small, you can start the seeds in smaller containers and transplant them into larger containers later.
The chart provides recommended, minimum size pots. Larger ones allow more room for roots, providing larger, healthier plants. Plants left in small containers too long will become root bound, decreasing growth vigor and production. Most tomatoes grown in larger pots will require staking.
The number of weeks recommended includes the period of germination at temperatures that are recommended by seed companies. To choose your planting date, decide when you want to sell or transplant your plant and begin germination the recommended number of weeks earlier. Seed companies can provide you with temperature and light/dark requirements as well. This information is often on the seed packages or provided in their catalogs.
Number of Weeks
Number of Weeks
Open Pot or Flat
Lettuce and most other greens are ready to transplant in 3 or 4 weeks, but they can be planted in March and transplanted into the garden in April in many locations. Broccoli and cabbage can also be transplanted before the last frost date for your area. Using temporary covers, leaves will be protected from frost and allowed to mature more quickly. Seedlings can also be transplanted into the greenhouse floor or beds and be raised without additional heat.
The number of weeks recommended for flowers in packs will provide a healthy green plant, except for short marigolds, impatiens and some petunias, which may start blooming in the packs. For blooms in containers the longer number of weeks are recommended.
Melon, cucumber, squash, and pumpkin plants grow quickly and need only 3-4 weeks before they can be transplanted into the garden. They should be started later, usually in April, and planted in May after the soil has become warm.
Greenhouse Space Saving Techniques
With a little garden space planning, it is possible to drastically increase the productivity and enjoyment of a greenhouse garden. Like with any great structure, one can start from the foundation and work up to the top to make sure each area complements the others and is an efficient use of the space.
If a greenhouse is on a deck or already has permanent flooring, it may not be possible to take advantage of some great underground space. If at all possible, there are many advantages to having a “flexible” greenhouse floor. To start with, some area of floor that is not covered can allow for cultivation of the soil or the addition of a perfectly blended soil mix to grow plants at the ground level. This will result in an automatic space saving because the roots of the plants are occupying space below the greenhouse floor level that otherwise would be wasted. All that is generally necessary for walking and working in the greenhouse is to leave a three to four foot corridor down the middle and the rest of the floor area can be planted. But even this center corridor can be a door to an underground gardening powerhouse.
The Underground Greenhouse Engine
One of the best ways to turn a greenhouse into a full scale organic gardening machine is to convert the center corridor into an underground composting and/or vermiculture center, and it is quite easy to do. Simply dig a trench three to four feet wide and two to three feet deep in the center of the greenhouse from end to end. Stack a brick barrier on the sides and ends and cover with strong plywood sections. The plywood makes a nice greenhouse floor for walking through and tending plants. Sections of the plywood can be lifted to reveal the perfect cool damp environment for composting and/or vermiculture and a dry box section can be included for garden supply storage.
Hydroponics and the Underground
Any discussion of greenhouse space saving techniques would be incomplete without some mention of hydroponics. Hydroponics presents a level of control and efficiency that is geared toward productivity and getting the most out of available space. Underground is the perfect place to put nutrient reservoirs. Many hydroponics systems require the reservoir to be below the plant growing medium and below ground reservoirs allow the plant grow beds to be as low as ground level. They do not take up space in the greenhouse and keep the nutrient solution cooler in summer and warmer in winter.
Using Floor Space Wisely
With a few cautions in mind, the stacking plant growing space with tiered benches or shelves can add greatly to productivity. It is important to consider how the shelves and plants themselves will shade other plants from light. Just as tall plants are generally positioned in the back of the garden so they will not shade shorter plants, it is important to observe the path of the sun in relationship to the greenhouse placement and plant accordingly. Place tall shelving and plants where they will not block too much light from other areas of the greenhouse. Shelves and racks are best made of mesh or screen construction which allows light, air and moisture to pass more easily. Always try to buy adjustable shelving. It is much more versatile and allows for spacing shelves based on the requirements of each crop. Specially designed triangular shelves are also available for the corners of the greenhouse to take advantage of what is often dead space. One last note on shelving, and just about anything else that is placed in the greenhouse, light colors are best because they reflect light allowing more of it to be absorbed by the plants.
Using Lights to Increase Productivity
As mentioned above, it is best to position benches, shelving and plants to take the best advantage of the natural light that is available to the greenhouse. That said it is possible to lengthen the growing season, volume of plants that can be grown and productivity with the use of artificial lights. T5 Fluorescent lights have several advantages for greenhouse space saving. They do not require large bulky external ballasts, and are very low profile and can be attached to the bottom of a shelf to provide light to the plants on the next shelf down. Just be sure to have proper channeling for moisture from the plants above. Bulbs are available in warm, cool and full spectrum and they produce very little heat allowing them to be positioned quite close to growing plants. They are available in 48 inch long 2, 4, 6 and 8 tube models that are perfect for any width shelf.
Using Space Saving Hydroponics Towers
Hydroponics towers are a growing innovation that is hard to ignore when it comes to getting the most from each square foot. These systems stack growing containers in clever configurations so that plants still get light, but are vertically stacked to save ground space. Several different varieties are available to suit almost any greenhouse application.
Last, but not least, because of their clear ceilings, greenhouses offer even more space for hanging plants. Once the floor and wall spaces have been planted, consider where hanging plants may work best without robbing too much light from other plants. As with shelves and other vertical plantings, it is important to study the path of the sun and shade in the greenhouse to determine where best to place hanging plants so the shade they provide is an asset not a determent to the greenhouse as a whole. This may be quite different depending on the season. In the summer, sun loving hanging plants may provide welcome shade when placed properly in the greenhouse. In the winter, they may need to be avoided entirely depending on the overall light requirements of the particular greenhouse application. Upside down tomato growers have also become popular for growing tomatoes and other plants hanging upside down and may make welcome space saving additions to the greenhouse.
It may perhaps be a habit from traditional outdoor gardening to look at the garden space as one dimensional and plan accordingly. A better approach is to take into consideration each level and surface from floor to sealing and how it will interact with the greenhouse as a whole. By taking a three dimensional view and planning the greenhouse garden from the floor up a better, more productive garden is within reach.
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Does My Greenhouse Need a Permit?
One of the first things a person must address when purchasing or building a greenhouse is what permits are required. The last thing a gardener needs is to purchase or build a greenhouse that doesn’t meet the local code requirements. Every community is different so there is no standard when it comes to permits for greenhouses. However, finding out which permits are necessary is a relatively simple process and most potential greenhouse owners should be able to take care of it themselves. There are two types of permits that need to be considered when building or purchasing a greenhouse. Those two types of permits are zoning permits and building permits.
A potential greenhouse owner should check with his or her local zoning department to see what is required. Zoning permits regulate the location of the greenhouse on the property. For example, a zoning permit will specify how close to the lot lines you are permitted to build. This could be the side, rear, or front lot lines and will be determined by your community’s rules and regulations. For instance, some communities may require that the greenhouse be built at least 20 feet away from the lot lines. Again, every community is different so be sure to check with your local zoning department to see how zoning permits affect your area.
Zoning permits will sometimes regulate the number of accessory buildings (greenhouses usually fall into this category) you can have on your property. Sheds and other outbuildings may be considered accessory buildings as well. The size of the building will also be taken into consideration by the zoning department. For example, the zoning department may decide that greenhouses that are less than 200 square feet need no additional building permits. In some cases, after meeting the zoning requirements, a potential greenhouse owner will have to get a building permit.
Building permits are typically issued by a county building department. Building codes look at the structural integrity and the physical appearance of the building. While many rural areas do not require any permits for accessory or agricultural buildings, most urban areas have some requirements. The building codes that address the structural integrity of a greenhouse generally deal with wind and snow loads and are specific to that geographical location. One of the first things to consider is whether you want a freestanding or attached greenhouse. Attached greenhouses normally require a building permit because they are considered an addition to the home and not an accessory building.
As far as building codes go, attached greenhouses are typically treated similarly to the addition of a sunroom. The building codes that deal with the appearance of the building will vary greatly from community to community. There may be regulations on how an accessory building appears. These rules are usually in place to maintain a high level of aesthetics in the neighborhood. In most cases, a greenhouse is welcomed by the community. Some homeowners’ associations or condo associations may have stricter requirements on accessory buildings. They may even have their own architectural review board which would need to approve the greenhouse design prior to construction. In the rare case that a greenhouse doesn’t meet the local requirements, you can apply for a variance. In most cases, a variance is possible because people like the idea of organic gardening in a greenhouse and local officials usually try to accommodate them.
Regardless of your location, experienced greenhouse manufacturers will help you work through the regulations process. In some cases, they may go as far as helping apply for variances or discussing your plans with a homeowners’ association. Greenhouse manufacturers with quality customer service won’t mind taking a few extra steps to ensure you get the right permits for your dream greenhouse.
For more information visit ArcadiaGlasshouse.com
The Best Plants to Grow in a Hydroponic Greenhouse
Hydroponic greenhouses can produce larger yields than a traditional greenhouse but for maximum success the grower must understand what to grow. Some plants may spread out too much to grow properly in a hydroponic greenhouse. Other plants may be cool weather plants and will not be able to stand the consistent high temperatures that other plants may need to thrive in. There are also plants that need special attention, if you decide to grow them in a hydroponic greenhouse and are too labor intensive.
Plants to Grow in a Hydroponic Greenhouse
Strawberries are one fruit that does quite well in a hydroponic greenhouse growing environment. Plants of this fruit are compact enough to fit in with the usual layouts of hydroponic greenhouses. You can set the plants out in a number of configurations and they will still thrive. Also, there are so many varieties to choose from depending on the size of berry and level of sweetness desired.
Potatoes and other root crops also work well, but only if they are given enough depth to grow adequately. You have to remember with these crops that they do a lot of their growing in the root area as well as up in their stems and foliage. If they are cramped for space, it will stunt their growth. You can choose the smaller varieties of the root crops, when available to help offer them enough depth.
Tomatoes thrive when grown hydroponically. Of course, they need to have a support system with this type of greenhouse setting just as they do in a traditional greenhouse or garden setting. Some varieties grow larger than other ones though, so choose the type you think you can provide the best support for in your particular setup. Some other vining veggies that need support include peas, cucumbers and pole beans.
There are many varieties of mint that do well in this type of greenhouse, because they enjoy wet conditions. Mints spread quite a bit and should be given enough space. Other than this requirement, your chosen mint whether it be peppermint, spearmint, ginger mint or another type of mint should produce nicely for you.
Basil is another herb to plan to grow in your hydroponic garden setup. The moist conditions provided to the herb through this system actually enhance its flavor. As with other plants, your yield will most likely increase with using hydroponic methods of gardening. Many other herbs do well too, but you need to check the growing conditions they need to make sure before planting them.
Various types of lettuce will provide you with more flavorful harvests. Some people only think of iceberg variety when lettuce is mentioned, but there is romaine, sweet butter and many more to choose from for growing your salad greens hydroponically.
Cabbage is one of the cool weather vegetables that does well in this environment. You may need to adjust growing conditions for the cool weather vegetables. This means you may need to grow the plants according to their natural seasons. You can change the temperature settings in your greenhouse according to the crops you decide to cultivate.
Bush-style green beans will adjust quite well with the typical conditions set up in a hydroponic system. You will be able to harvest plenty for your table and have additional beans to can or freeze. The size of these is easier to deal with than the pole beans, even though with the right support, as mentioned earlier, you can also grow pole beans.
Greenhouse Construction: Planning for Snow Loads and Wind Loads
With all the decisions to be made when contemplating purchasing or building a greenhouse, it may be easy to overlook snow and wind. However, a gardener needs to seriously consider how a greenhouse will handle snow and wind loads. As you can imagine, heavy snow fall or intense wind gusts can cause serious damage to a greenhouse structure. Unfortunately, not all greenhouse manufacturers are straightforward with snow and wind load ratings or requirements. It can also get confusing because many of the smaller hobby greenhouses are not required to meet the same codes as more permanent greenhouse structures. One thing is certain, potential greenhouse owners need to take it upon themselves to understand their geographical location’s building code requirements and which greenhouse designs will meet those requirements.
The very first thing a gardener should do before constructing or purchasing a greenhouse is to check with the local building department (where building codes are issued) and see what the snow and wind load requirements are for his or her geographical location. Regardless of the type of greenhouse you plan to have (stand alone or attached) it is very important to check and see what the building code requirements will be. With this information you can go back to the greenhouse supplier or builder to see which greenhouse design will meet those requirements.
Small hobby greenhouses with a stamped aluminum construction generally will not require building permits but will rarely meet the requirements for snow or wind loads. Most hobby greenhouses are not designed to last a lifetime and will quickly degrade. Growers who are looking for a more permanent structure should look for greenhouses that utilize extruded aluminum framing instead of stamped aluminum framing.
Higher quality greenhouses with extruded aluminum framing will most likely meet local building code requirements. These greenhouses are designed to be a more permanent structure. Generally speaking, greenhouses need to withstand 30 pounds of snow per square foot (an equivalent of about four feet of snow) and wind gusts up to 105 MPH to meet most of the code requirements throughout the United States. Greenhouses built with quality extruded frames will not only be able to meet the wind and snow load requirements but will also be considered a truly permanent structure that is designed to last a lifetime.
In locations where snow loads or wind loads exceed the norm, additional bracing or advanced technological designs can be used to create additional strength. Some of the older greenhouses use heavy cross ties to meet higher snow load requirements. Many of the newer greenhouses are utilizing sophisticated engineering designs, like the scissor truss. The scissor truss design not only adds strength but also, because it eliminates the need for cross ties, allows for additional head room in the greenhouse.
If you are in the market for a greenhouse that will handle heavy snow and wind loads and last a lifetime, you should seriously consider a greenhouse with extruded aluminum framing. Small hobby greenhouses are suitable for some applications but should not be considered a permanent structure and certainly shouldn’t be expected to withstand heavy snow loads or strong gusts of wind. A quick trip to your local building department will give you all the information you’ll need for snow and wind load requirements. With that information you can discuss all of your options with your greenhouse supplier.
For more information visit Arcadiaglasshouse.com.
Photo Description: The innovative “Scissor Truss” design provides extra strength and higher headroom for larger spans in greenhouses that meet local building codes for snow load and wind loads specifications.
Greenhouse Lighting Options
Whether it’s to provide supplementary lighting or to extend the length of the photoperiod, some greenhouse growers are equipping their greenhouses with artificial light sources. Before purchasing a lighting system for a greenhouse, a grower should first determine which type of lighting system will best meet their needs.
T-12 fluorescent lights are the standard four foot fluorescent lights commonly used in garages and shops. In fact, many people refer to T-12 fluorescents as “shop lights”. Although T-12 fluorescents are just fine for starting seeds indoors or illuminating indoor houseplants, they usually lack the intensity and efficiency to provide light to plants in a greenhouse.
T-5 fluorescents are a more powerful and efficient version of fluorescent lighting. Still available in four foot lengths, the skinnier T-5 bulbs are 54 watts each. Specialty horticultural enhanced bulbs are available for T-5 fixtures in both the warm (red) and cool (blue) spectrums. The warm spectrum bulbs are rated around 3000 K and the cool spectrum bulbs are rated around 6400 K. During the fruiting or flowering stage of growth most plants require a higher percentage of red spectrum light. During the vegetative stage of growth plants require more blue spectrum light. Many T-5 fixtures hold multiple bulbs and allow “banks” of bulbs to be turned on or off. In other words, it is possible to set up a T-5 fixture to customize the light spectrum in your greenhouse. During the vegetative stage, the bank with the blue bulbs should be on. When the transition or flowering stage begins the banks with the red spectrum bulbs can be activated in order to give the plants the more appropriate spectrum for that stage of growth. Generally speaking, T-5 fluorescents are the most cost effective option for the hobby greenhouse grower.
Metal halide is a type of high intensity discharge (HID) lighting that can be used in greenhouses. Metal halide lighting systems are more intense than fluorescent lighting fixtures and are a good choice when growing roses, tropical palm, or other plants that will require more intensity than fluorescents can provide. Metal halides generally produce a white or blue spectral output which makes them a good fit for vegetative growth. Metal halides are commercial quality fixtures that come in 400, 600, or 1,000 watts. Metal halide lighting systems require three components: the bulb, the ballast and the reflector or socket base. These lighting systems create a good amount of heat and can be quite expensive to operate. However, in some cases, metal halide is the only way to provide plants with the intense blue light spectrum they require for vegetative growth.
High Pressure Sodium
Like metal halide, high pressure sodium is a type of HID lighting. These lighting systems are also available in 400, 600, and 1000 watts. The biggest difference between high pressure sodium and metal halide is the spectral output. High pressure sodiums provide a good amount of red spectrum. This makes these lighting systems a great fit for fruiting or flowering plants. Since high pressure sodiums are also a type of HID lighting system, they will also require a ballast and reflector or socket.
If you have determined that your greenhouse will require a HID lighting system and you plan to provide artificial light during the plant’s vegetative and flowering stages, you should look into a convertible ballast. Convertible ballasts allow the grower to use both metal halide and high pressure sodium bulbs in the same fixture (but not simultaneously). A grower can use his or her metal halide bulb during the vegetative stage and then switch to a high pressure sodium bulb during the flowering stage.
There is certainly an emerging opportunity for LED lighting systems to be incorporated into the greenhouse. Consumers should be aware that LEDs are very spectral specific and they need to make sure the LED light system they purchase provides the spectral output required by their plants. Unfortunately, there are a lot of variables to consider when comparing LED lighting fixtures. The light spectrum, actual wattage, and type of lens used are all things to consider when purchasing a LED system. There is also a wide variance in overall quality. Many of the cheap LED fixtures will not stand up to the conditions found within a greenhouse. There is no doubt that LED lighting systems will continue to shape the future of horticulture but it is important for consumers to closely examine what they are purchasing.
Sizing Heating and Cooling Equipment for a Greenhouse
Maintaining consistent temperatures is one of the most important aspects of greenhouse gardening. During the hot, summer months, most greenhouses will require some sort of cooling to ensure the temperatures don’t get too hot. During the cold winter months, most greenhouses will require some sort of heating to ensure temperatures do not get too cold. Before purchasing any heating or cooling equipment, a grower should take a close look at his or her space and make a few sizing calculations. With these calculations and a few considerations, a horticulturist can be sure to get the properly sized heating and cooling devices needed to keep the greenhouses’ temperature in check.
The most effective way to cool most greenhouses is with a powered fan. A powered fan will actively draw fresh air through the greenhouse and exhaust it outside of the greenhouse. The cooler air, from outside along with a natural evaporative effect, help keep the greenhouse cooler. In fact, a powered ventilation system will typically make a greenhouse run 10 degrees cooler than if the greenhouse is passively cooled (vents only). To make sure there is enough cooling power, a gardener must “size” the fan that will be needed for the given garden space. Fans are rated by their CFM or cubic feet per minute. Ideally, a greenhouse should have all of its air exchanged in 1-2 minutes. A simple and straightforward way to determine the needed CFM is to multiply the length by the width by the wall height of the greenhouse as shown below:
Length x Width x Wall Height = Recommended CFM (Cubic Feet of air volume per Minute)
Granted, this is not an exact calculation of the greenhouse’s cubic feet because it does not take into consideration the roof pitch, etc. However, this measurement is accurate enough to properly size a powered fan for a greenhouse. Once a grower has calculated the recommended CFM, he or she can set out to find a fan that meets that criteria. For example, a greenhouse that is 20 feet long, 10 feet wide, and has a wall height of 10 feet will have a recommended CFM of 2,000 (20 x 10 x 10 = 2,000). The owner of this greenhouse should purchase a fan with a minimum of a 2,000 CFM rating.
A gardener planning to heat his or her greenhouse with gas or electric must first determine the size of the heater. The best way to determine this is to figure out how many BTUs will be required to heat the space. This is done by first calculating the total square footage of exposed surface area. In other words, the exposed wall and roof surface area. Remember that the roof area, due to the pitch, will not be equivalent to the area of the floor. In fact, the exposed surface area of the roof will be larger than the floor area footage. After determining the total square footage exposed, the grower must determine the maximum desired temperature in the winter (the temperature at which the gardener wants the greenhouse to operate during the winter months) and the minimum temperature outside of the greenhouse. Remember to be realistic when making the temperature determinations. In other words, base your calculations on average temperatures rather than the extremes. The BTU calculation is completed when you multiply the total exposed surface area by the difference between the desired temperature and the outside minimum temperature, and then divide that number by the R-value of the greenhouse material. It’s important to remember when calculating the required BTUs that gas heaters operate at 80% efficiency compared to electric heaters which operate at 100% efficiency. In other words, a grower must take the lower efficiency into consideration in his or her calculations or he or she must find the gas heater’s output BTU rating (which already takes the 80% efficiency into consideration).The following is the formula that should be used to calculate the needed BTUs:
Sq. Ft. Exposed Surface Area x ( Tmax – Tmin ) ÷ R Square Feet of Glass or Poly Surface Area x (Desired Temperature Inside – Minimum Temperature Outside) ÷ R-value
Here are the R-values of some commonly used greenhouse glazing materials:
Glass – Single Pane
Polycarbonate – 8mm Twinwall
Polycarbonate – 8mm Triplewall
Glass – Double Pane
Polycarbonate – 16mm Triplewall
Polycarbonate – 16mm Five-wall
Glass – Double Pane Low-E
Although all of these R-values may seem low when compared to a home or commercial building, there is a significant difference when comparing these materials to each other. For example, a greenhouse with single pane glass will require twice the BTUs (and cost twice as much to heat) as a greenhouse with a triplewall polycarbonate. In other words, when compared to each other, the R-values of these materials are quite significant, especially when considering how the required heating load is affected.
With a few simple calculations, any greenhouse grower can determine the appropriate size cooling fan and heater for his or her greenhouse. Greenhouses that have properly sized heating and cooling equipment will not only allow a gardener to extend the growing season but will also efficiently control temperatures in the greenhouse.
For more information visit ArcadiaGlasshouse.com.
Grow All Year Round with Artificial Heat
A gardener who owns a greenhouse has the capability of extending the growing season by a few months each year. There are even a select few greenhouse gardeners who can get away with growing year round without adding a heating system. In most climates, however, during the winter months the nighttime temperatures become too cold for most plant species. In order for most greenhouse hobbyists to keep the greenhouse operational year round, some sort of heating system will need to be added. The three most common ways to heat a hobby greenhouse are with gas, electric, or passive solar heat.
Heating a greenhouse with gas is the least expensive option. The cost of heating a greenhouse with gas is the main advantage of gas heating and is the main reason people choose gas heating over other options. Beware of open flame heaters for greenhouse applications. These heaters will emit ethylene gas which can affect budding plants, such as orchids, to the point where their blossoms will not form or will fall off altogether. The other problem with open flame heaters is they have safety oxygen sensors which will automatically turn off the unit when depleted oxygen levels occur. This is a great safety feature for a heater within a home but in a greenhouse it can cause some problems. Many of the newer greenhouses are practically air tight which means they can get depleted oxygen levels fairly easily. If the heater turns off during the night, all the plants in the greenhouse could perish. Gas heaters that have a flue and are power exhausted are the best for greenhouse applications. These heaters will need to have a hole punched into the side of the greenhouse for the exhaust. All in all, an average gas heater for a greenhouse runs at 80% efficiency (mainly due to the heat loss through the exhaust ports).
Because there is no need for ventilation with electric heat, this type of heating is the most efficient. Electric heating runs at 100% efficiency. However, electricity is expensive and heating a greenhouse year round with electricity alone may be too expensive for many gardeners’ greenhouse budgets. However, there are some ways a gardener can supplement heat naturally to offset some of the cost of heating with electricity. For example, passive solar heat can be used to offset some of the cost associated with electric heating. If you do choose to go with an electric heater, it is best to get a 240V heater which will have plenty of heat capacity. Over the long run, 240V units save money and are very reliable. If you must go with a 120V unit, try to avoid infrared heaters or heaters that transfer heat to objects instead of heating the air. For greenhouse applications, a gardener will need a heater that will heat the air within the greenhouse. The best inexpensive 120V heaters for greenhouses are the oil-filled radiator-style heaters. If placed near a fan, these small heaters can adequately heat some small hobby greenhouses during the winter months.
Passive Solar Heat
Passive solar heat refers to collecting heat from the sun’s radiation during the daytime and releasing that heat into the greenhouse during the nighttime. This is usually done with water or some other thermal mass that is capable of absorbing and holding heat for a duration of time. One technique is to line the north wall of a greenhouse with black water containers. When placed on the north wall, these containers will not shade light from reaching the plants in the greenhouse; instead, they will absorb light and heat that passes through the greenhouse to the north wall. When the sun sets, the heat that is held by the water will slowly dissipate into the greenhouse environment. When passive solar heat is used in conjunction with electric heat, it can significantly reduce the annual cost of heating a greenhouse.
For more information please visit ArcadiaGlasshouse.com.
Photo: The pictured 5-gallon water jugs are painted black and stacked against the north wall of the greenhouse to act as Passive Solar Heat Collectors in the winter.
Foundations for Greenhouses
When setting up a greenhouse, one of the most important aspects of the construction process is the foundation. There are a few different types of foundations that can be used for greenhouses. The foundation used will be determined by the type of greenhouse, the building codes and, in some cases, personal preference. Essentially, the foundation is the complete system on which the greenhouse structure sits. One of the key components of a foundation is the footing. The footing refers to the point at which the structure meets the soil. This is the section that the structure rests upon. Footers are not always necessary for a standard hobby greenhouse. In situations where they are necessary, footers are typically poured concrete and their exact depth is determined by local building codes and the location’s frost levels. Footers help to prevent sagging or the dropping of the structure’s walls and/or floor into the ground. The choices for a greenhouse’s foundation are typically dependent on the type of greenhouse structure that will be built.
If you have an attached even-span or a lean-to greenhouse there is a need for footers with the foundation. Local building codes will determine the exact depth needed for the footers. Basically, attached greenhouses require frost free footers that will not shift or move. As the ground freezes and thaws structures without the proper foundation could move or sag. If you plan on building an attached greenhouse, you should also plan on a more extensive foundation. In most cases, the gardener is already planning on the expense of a foundation for the attached greenhouse so the cost of pouring a concrete pad for the floor is seen as a minimal addition. However, some gardeners still prefer the moist, earthy smell of gravel and will have a gravel floor installed. A limestone screening and weed barrier placed beneath the gravel will ensure no weeds start growing from the floor. Some gardeners prefer a gravel floor for its natural drainage properties as well. Regardless of the floor material chosen, the footing requirements will not change.
Freestanding Hobby Greenhouses
Smaller, freestanding greenhouses do not have the same requirements as an attached greenhouse and, therefore, give the grower more options when it comes to the foundation and floor. Freestanding greenhouses can have a concrete slab poured without a deep foundation. In fact, if the greenhouse doesn’t have a knee wall, it can be placed directly on a cement slab or it can be placed on a 4’ x 6” treated lumber base. The best wood choices for a lumber base are usually cedar, redwood, or cypress. Rebar can be added to the wooden base for additional support if desired. For a freestanding greenhouse with a knee wall (a brick or cinder block wall that stands roughly knee high), a 12” x 12” surface footer is required. This is because the additional weight of the brick or cinder blocks could otherwise sink in to the soil and affect the structural integrity of the greenhouse. Knee walls are usually installed to add design appeal and for their natural high thermal mass. During the day, the stones absorb heat from the sun and during the night, they act as a passive heater as the heat is released into the greenhouse.
Generally speaking, greenhouses that are attached to the home or freestanding greenhouses that are more than 120 square feet will need building permits or will have to be up to code. However, it is always a good idea to check the local city codes to see what permits and footings are required before beginning construction on any greenhouse.
For more information visit ArcadiaGlasshouse.com.
Greenhouse Shade Cloth Options
A shade cloth is used in a greenhouse for two reasons. First, to protect plants from getting burned by intense sunlight and second, shade cloth is a way to help keep a greenhouse cooler during the hot summer months. Shade cloth can be made from different materials but all shade cloth can be purchased in different filtration ratings. In other words, a gardener can select a percentage of shading that will best fit his or her needs. In most cases, a shade cloth will shade 50%, 60%, or 70% of the sunlight. The higher percentage (70% or greater) is usually reserved for situations where the greenhouse is receiving an abundance of intense sunlight; such as a south-facing greenhouse that receives full sun in the summer months. Shade cloth is usually sized according to the particular greenhouse. In other words, shade cloth is usually custom built for a particular situation. The shade cloth has grommets placed every four feet for hanging on hooks or guide wires depending on the application. A closer look at some of the shade cloth options will give greenhouse gardeners an idea of which shade cloth option will work best for them.
Aluminet is one of the most affordable and effective shade cloth materials available. Aluminet can be hung on the interior of a greenhouse and placed flush against the walls or ceiling. Aluminet is unique because it not only shades sunlight but it also reflects heat. The biggest advantages of Aluminet are that it not only shades the light but also helps to effectively cool the greenhouse by reflecting a portion of the heat away from the structure. Aluminet is very cost effective and a great choice for home hobbyists. If aesthetics are important (as they are with many home gardeners), the interior hung shade cloth does not take away from the natural beauty of the greenhouse structure.
Black nylon shade cloth hung on the exterior of the greenhouse is another shade cloth option. The hooks for the grommets are on the outside of the structure and the shade cloth is hung around the exterior of the greenhouse. This type of shade cloth costs about the same as Aluminet and does a good job of filtering the light. Although the greenhouse will be cooler than without the shade cloth, due to its black color, this type of shade cloth does little to reflect the heat away from the structure. As can be imagined, a shade cloth hung on the exterior of the greenhouse will affect the aesthetics of the greenhouse. There is also some additional maintenance with exterior hung shade cloth as they tend to accumulate dirt, dust, etc.
Motorized or Manual Guide Wire Shade Cloths
Motorized shade cloth systems are so expensive they are generally reserved for large, commercial greenhouses. These systems have guide wires where the shade cloth is attached. When needed, a small motor pulls the shade cloth into place. Many commercial greenhouses utilize guide wires without motors as well. Similar to opening or closing a shower curtain, a large span of shade cloth can be opened or closed within the greenhouse. The biggest disadvantage of motorized or manual guide wire shade cloth systems is the shade cloth is never flush with the walls or ceiling of the greenhouse. This means that the heat is still entering the greenhouse. However, there are some situations where it is necessary for the shade cloth to shade a section of the greenhouse. For example, seedlings or light sensitive plants can be protected from intense light by being sectioned off with some shade cloth.
For most hobbyist growers finding a shade cloth that fits the budget and still performs up to par are the priorities. Gardeners with glass greenhouses which have south or west exposures almost always need to implement some sort of shade cloth. If reducing heat in the greenhouse is as important as eliminating hotspots in the garden a product like Aluminet would be a good fit. Regardless of the particular material chosen, a shade cloth is the best way to keep plants from being harmed by the intensity of the sun during the summer months.
For more information please visit ArcadiaGlasshouse.com.
Keeping Your Greenhouse Cool in the Summer
In order for the plants in a greenhouse to continue growing rapidly during the summer months, a greenhouse gardener needs to make sure that the temperature within the greenhouse doesn’t get too hot. There are a few different ways that greenhouse growers can maintain cooler temperatures during the heat of summer. A grower usually chooses a cooling method based on the size of the greenhouse and his or her budget. The most common types of cooling devices used in greenhouses are based on water evaporating which cools the air within the growing space. The most commonly used systems are wet wall systems, portable evaporative coolers, foggers, and humidifiers.
Wet Wall Systems
Wet wall systems are the most popular and efficient way to cool large, commercial greenhouses. These systems consist of cooling pads encased in aluminum housing. The aluminum housing appears similar to a honey comb. The honey comb design allows air to pass over the cooling pads which are kept drenched in water. The air is cooled significantly as it passes through the wet pad on its way into the greenhouse, much like a radiator cooling an engine. After entering the greenhouse, the evaporative effect cools the growing space. The powered fans (placed on the wall opposite the wet wall system) are the driving force for the air movement. The motorized shutters which allow air to enter the greenhouse are usually thermostatically controlled to open and close as determined by the temperature. Wet wall systems are fairly expensive and more elaborate in their installation. This is because the water used in a wet wall system is continuously recirculated and requires a fair amount of plumbing. Because of their expensive and more elaborate design, wet wall systems are usually only used in larger commercial greenhouses.
Portable Evaporative Coolers
Portable evaporative coolers are a cooling device which is much more commonly used by home hobbyist greenhouse growers. Portable evaporative coolers are completely self-contained, movable, and relatively inexpensive ($500-$1000 depending on size). Portable evaporative coolers contain a similar pad to that used in wet wall systems. Like wet wall systems, air is drawn in and forced over the wet pad to create an evaporative cooling effect. Portable evaporative coolers usually contain a float valve and are connected to a garden hose to maintain the water level in the tank as the water evaporates. Portable evaporative coolers work best when they have access to fresh air. In other words, for the best effect, portable evaporative coolers should be placed near the greenhouse entry or a fresh air intake vent. Portable evaporative coolers are thermostatically controlled and can easily be stashed under a bench or out of the way when not in use. Portable evaporative coolers are a great way for home hobbyist greenhouse gardeners to maintain cooler temperatures during the hot summer months.
Fogger or Humidifier
For small hobby greenhouses, a fogger or humidifier can serve as an evaporative cooling system. A fogger is a device that emits water in a fine fog. These devices can be placed directly behind a circulating fan to blow the water-cooled air around the greenhouse. As the water evaporates, it creates a cooling effect. A humidifier found at a big box store can be set up in a similar fashion. When placed behind a circulating fan, the cool moist air can be blown across the greenhouse for an evaporative cooling effect. Both foggers and humidifiers emit water droplets so small that the plants within the greenhouse will not get wet. Instead, the water quickly evaporates and cools the greenhouses climate in the process.
When discussing cooling systems within a greenhouse, some gardeners ask about mist systems. Although a mist system will cool a greenhouse, they are generally better suited for irrigation. The water droplet size from a mist system is much larger than that of a fogger or humidifier and this causes the plants to actually get wet which can create a whole new series of moisture related problems during the hot summer months.
By maintaining temperatures within the desired range for plant growth, a greenhouse gardener can ensure that he or she maintains vigorous growth even during the peak heat of the summer months. Whether a gardener is attempting to cool a large commercial greenhouse with a wet wall system or a small hobbyist greenhouse with a portable evaporative cooler or a humidifier, evaporative cooling is the best way to ensure that the plants beat the heat of summer.
For more information visit ArcadiaGlasshouse.com.
Size Matters in a Greenhouse
They say that everything is bigger in Texas. Well, Texas is a fine state but you don’t have to live there to enjoy the benefits of a big greenhouse. A good general rule is to figure out what size footprint you need for growing things and then double it. That should be about the right size for your greenhouse. Here’s why I suggest this approach to sizing:
Easier Heating and Cooling
Smaller structures heat up too quickly and cool down too quickly. Think of how temperamental a cold frame is. If you don’t quickly vent them, they’ll cook your plants in a matter of a couple of hours. The same hold true for a small greenhouse, so bigger is better.
Room to Work and Grow
You need room to work in addition to the space allocated for growing. A greenhouse footprint based on sufficient room for growing plants is a bit like space planning for an office. It’s nice if the desk fits well in the room, but you also need room for your large office chair, a bookcase and a filing cabinet. And, you’d like to be able to push back from the desk and lean back in your chair as well. All of this requires “swinging room.”
Room to Relax
Don’t forget about room to relax. When you’re taking a break from gardening, you’ll want some space where you can sit down and enjoy the splendor that you’ve created. What could be more enjoyable than relaxing in a comfortable chair and enjoying the sights and smells of your herb garden or tomato jungle?
Room for Storage
Lastly, you need room for features like tool storage, a hose rack, walkways, a sink for rinsing off your root vegetables and perhaps a work table or space dedicated to starting seeds in covered, lighted and heated seedling greenhouse within your greenhouse. Also, don’t forget that a drum wall for passive solar energy storage takes up about four square feet per drum. When you start to think about it, there’s plenty of reason to have room in a greenhouse for things that aren’t green. You simply can’t expect to “dance” in a hall closet. You need room to spread out.
I’m not advocating a huge greenhouse, but we need to be aware that there are people, accessories, resources, tools, walkways and activities that need to be included in our indoor growing spaces – along with all the plants. If you forget about room for these types of things, you’ll soon come to the conclusion that you built a structure that simply isn’t big enough for your needs and longer term interests.
The Importance of Ventilation in a Greenhouse
Proper ventilation is imperative for a greenhouse to function properly. The ventilation system of a greenhouse provides fresh air to the plants (CO2), helps to control temperature and humidity, and reduces the likelihood of disease. Greenhouses are generally enclosed structures that will not ventilate entirely on their own. In order to ensure that proper ventilation in the greenhouse is achieved, gardeners must install either a passive or powered ventilation system.
Passive Ventilation System
A passive ventilation system is a ventilation system without powered fans. Instead, the greenhouse is ventilated via convection (hot air becomes less dense and rises) through the ridge vents. In addition to the ridge vents, a passive ventilation system needs intake vents to allow cool air to enter the greenhouse and displace the hot air as it rises. These intake vents are generally placed on the lower portion of the side walls of a greenhouse. The largest advantage of passive ventilation systems is that they are virtually silent. This can be advantageous for a gardener whose greenhouse is attached to his or her home and the noise of a powered fan would be a disturbance. The biggest disadvantages of a passive ventilation system are cost, maintenance, and efficiency. Most people don’t know that a ridge vent system will cost 3-4 times as much as a PVS (powered ventilation system). Also many people do not understand that maintenance is required with a passive ventilation system. The ridge vent needs to be kept free of debris and cleaned periodically. Also, the pistons on the vent system will need to be lubricated. Last, but not least, because air is not being forced through the greenhouse, a passive ventilation system is not as efficient as a powered ventilation system. All in all, passive ventilation systems are a great fit for greenhouses where the noise of a powered fan would be an annoyance.
Powered Ventilation System (PVS)
A powered ventilation system for a greenhouse is a ventilation system with a powered fan and intake vents. The cubic feet of the greenhouse space will be the determining factor for sizing a fan system. The minimum goal is to get the cubic volume of air turned over in less than two minutes. In many cases, a fan will be sized to turn over the air in less than one minute. A quick turnover makes it much easier to control temperature and/or humidity, keeping the greenhouse about 10 degrees cooler than a passive cooling system. The fan should be installed on the top section of the wall opposite of the intake vents and screen door. In other words, the intake vents should be installed on the same wall as the door and the fan should be installed on the top of the opposite wall. This ensures that the fresh air entering the greenhouse travels across the greenhouse before being evacuated. Powered ventilation systems are usually set up with a thermostatic control which will turn on the fan when the set-point temperature is reached. The intake vents are synced with the fan so they will open at the same time the fan is activated. In order to maintain the highest level of performance, the thermostat sensor should be placed at plant height.
In addition to the cooling/exhaust fan of a PVS, a greenhouse should also be equipped with a circulating fan. Circulating fans provide continuous air movement within the greenhouse which helps to maintain uniform temperatures and humidity while also increases the structural integrity of the plants (much like the wind strengthens plants in nature). Greenhouses with circulating fans are the most effective and efficient for maintaining desirable atmospheric conditions.
Whether you choose a passive or powered ventilation system, making sure a greenhouse is properly ventilated is crucial to creating an ideal growing environment for plants. A greenhouse’s temperature, humidity, and ambient CO2 levels are all determined by the ventilation system. In other words, the ventilation system is one of the most important determining factors over the way plants will perform in a greenhouse and should be contemplated by every potential greenhouse gardener.
For more information visit ArcadiaGlasshouse.com.
Photo – A Powered Ventilation System (PVS) and circulating fans provide optimum cooling efficiency.
The Different Types of Attached Greenhouses
Attached greenhouses are exactly what they sound like: greenhouses attached to another structure. In many cases, the other structure is the gardener’s house. Attached greenhouses include lean-to greenhouses, window-mounted greenhouses, and attached even-span greenhouses.
Lean-to greenhouses are built against an existing building using that structure for one or more of its sides. In most cases, lean-to greenhouses are attached to a house. Lean-to greenhouses can be as long as the length of the building they are attached to or as short as desired. Because of their particular construction, lean-to greenhouses are typically limited in width to roughly 12 feet wide. The advantages of a lean-to greenhouse are accessibility to electricity and water (when placed against a house with electricity and water) and decreased cost of materials (since one of the main walls is an existing structure). Lean-to greenhouses typically require less heating than freestanding greenhouses. This can save a gardener a significant amount of money especially if he or she is located in a colder climate. Another advantage of lean-to greenhouses is accessibility. Since the greenhouse is so close to the home, the gardener has easy access to culinary herbs and vegetables. Accessibility also makes it easier for gardeners to keep up with greenhouse maintenance. The last advantage of lean-to greenhouses is that they are relatively simple to construct or inexpensive to purchase. Building a custom lean-to greenhouse can be an easy project for hobbyists who are not usually considered handy at construction. In fact, dozens of basic plans for homemade lean-to greenhouses can be found on the internet. Building one’s own greenhouse can give gardeners a feeling of self-reliance. For gardeners who don’t wish to build their own greenhouses, a lean-to greenhouse kit is an inexpensive way to get into home horticulture. The biggest disadvantages of lean-to greenhouses are their limited space and, in some cases, limited light. Whenever possible, lean-to greenhouses should be constructed on the side of the home that will receive the most sunlight (south side). Even when perfectly placed, a lean-to greenhouse will not receive as much light as a freestanding greenhouse.
Window-mounted greenhouses are special structures built into a window frame of a home, usually on a south facing wall. These handy, little greenhouses are a great way for hobbyists to keep their thumbs green year-round. Window-mounted greenhouses give hobbyists the opportunity to have fresh culinary herbs and ornamental plants at their fingertips while in the comfort of their own homes. The advantages of window-mounted greenhouses are they are relatively inexpensive and allow growers to harvest plants from inside their homes. In some cases, window-mounted greenhouses can help with heating a home as they let in passive solar heat. The disadvantage of a window-mounted greenhouse is space. These greenhouses are relatively small which limits the species and number of plants a gardener can grow.
Attached Even-Span Greenhouses
Attached even-span greenhouses are less common than lean-to greenhouses but also share a wall with an existing structure. The difference is that an attached even-span greenhouse appears very similar to a freestanding greenhouse except it is attached to an existing structure at one gable end. In other words, it doesn’t “lean” against the existing structure, but instead has its own symmetrical roof. Attached even-span greenhouses can be much larger than lean-to greenhouses and there are countless design possibilities. The largest advantage of an attached even-span greenhouse is they are less expensive than a freestanding greenhouse and can provide a lot of growing space. As with lean-to greenhouses, water and electricity are more accessible. Disadvantages of an attached even-span greenhouse are increased cost compared to other attached greenhouses and reduced light from shadowing of the attached structure (usually a home).
Greenhouse Glazing Options
When purchasing a greenhouse, a gardener is faced with a few options in regard to the type of material the transparent panels are made from. Although all greenhouses are designed to allow sunlight to reach the plants, there can be a difference in the way a garden performs due to the materials that make up the greenhouse. Hobbyists looking to set up a greenhouse have essentially three choices when it comes to the greenhouse’s glazing options: single pane glass, double pane glass, or multi-wall polycarbonate. Each glazing option has its own advantages and disadvantages which means growers should examine each before making a final decision.
Single Pane Glass
The older-style single pane glass greenhouses with overlapping glass are less than desirable due to the fact that many of them are not adequately sealed. This can cause a series of problems including inefficiencies with heating and cooling and humidity/moisture problems. The good news is that most of the newer-style single pane glass greenhouses have full length glass panels and are sealed which solves many of the problems associated with the outdated, leaky designs. One great thing about single pane greenhouses is that they look fantastic. Single pane glass greenhouses are very aesthetically pleasing and will only cost a little more than a polycarbonate greenhouse. However, single pane greenhouses should probably be avoided by gardeners in northern climates. Single pane glass greenhouses are the least energy efficient type of greenhouse. In fact, a single pane greenhouse will have double or even triple the heating costs when compared to a double pane or multi-walled polycarbonate greenhouse. Single pane glass greenhouses allow for 92% light transmission. This can be an advantage or a disadvantage depending on your climate and the location of the greenhouse. Greenhouses should let in as much sun as possible, right? In some cases, a glass greenhouse can allow too much light to reach the plants which may create “hot-spots” and cause significant damage to the plants. The gardener may need to install a shade cloth in the greenhouse to rectify this problem. All in all, single pane glass greenhouses are a good choice for gardeners who will not be heating the greenhouse or who strongly desire an aesthetically pleasing greenhouse.
Double Pane Glass
Double pane glass greenhouses are the bee’s knees when it comes to greenhouses. Double pane glass greenhouses are designed to be the most energy efficient and offer gardeners half the heating costs associated with single pane glass greenhouses. In other words, gardeners can look at a double pane glass greenhouse as a long term investment that will pay for itself in the form of energy savings. Double pane glass can also include a special low-e reflective coating on the inner pane of glass which reflects heat and acts as an insulator. For a serious hobbyist searching for the nicest looking and most energy efficient greenhouse, a double pane glass greenhouse is for you. The only real disadvantage of a double pane glass greenhouse is the initial cost. Double pane glass greenhouses are by far the most expensive option but, again, when examining the long term energy savings, the increased initial cost of the greenhouse would be paid back over time.
Another glazing option for a hobbyist looking to set up a greenhouse is polycarbonate. Multi-wall polycarbonate greenhouse material comes in a variety of thicknesses (8mm triple-wall, 16mm 5-wall). The construction of the material varies slightly but all include multiple walls inside of the material which form channels that hold air. This airspace is important because it creates insulation value. A polycarbonate greenhouse offers similar energy efficiency to a double pane glass greenhouse. One advantage of polycarbonate material is that it naturally diffuses the sunlight. By diffusing the sunlight, polycarbonate greenhouses reduce the likelihood of “hotspots” and give the plants in the greenhouse an even distribution of light energy. Polycarbonate panels that are slightly tinted can also be installed in the roof of the greenhouse to reduce or eliminate the need for shade cloth. This is a great option for gardeners in hot, sunny locations. Although polycarbonate is not as aesthetically pleasing as glass, these greenhouses offer the best upfront value. Polycarbonate can also be used to retrofit older greenhouses to increase efficiency.
Please remember when making a decision regarding your greenhouse glazing options that efficiency and greenhouse performance are dependent on many factors including your geographical location and the orientation of the greenhouse. Where you live and what you grow will make a big difference in your selection of a greenhouse and greenhouse glazing. Take the time to explore all of your options to find the greenhouse design that will best serve your purposes.
For more information, please visit ArcadiaGlassHouse.com.
Choosing an Attached or Freestanding Greenhouse and Greenhouse Orientation
When setting up a greenhouse, one of the first things a gardener needs to decide is whether the greenhouse will be a freestanding or an attached greenhouse. A closer look at some of the advantages and disadvantages of each will give a gardener a better idea of which type of greenhouse will best suit his or her needs.
Advantages of an Attached Greenhouse
One of the biggest advantages of an attached greenhouse is that they are generally more energy efficient. This is because one wall is already heated by the home. Another advantage of an attached greenhouse is accessibility. Many attached greenhouses are accessible from the living space which makes entering the greenhouse especially convenient. Attached greenhouses can also add aesthetic value to a home. In many cases, a greenhouse will enhance and/or complement the architecture of the home.
Disadvantages of an Attached Greenhouse
The disadvantages of an attached greenhouse are that attached structures will require a frost-free footer and a foundation. This can be an added cost to the project. Also, building codes are generally more stringent for structures attached to living spaces.
Advantages of a Freestanding Greenhouse
Perhaps the biggest advantage of a freestanding greenhouse is that there are fewer limitations regarding size, height and style. Another significant advantage is that freestanding greenhouses usually have better lighting conditions because they can allow light to enter on all four sides of the greenhouse.
Disadvantages of a Freestanding Greenhouse
A disadvantage of a freestanding greenhouse is an increased heating cost during colder months. Due to all four sides being exposed to the elements, freestanding greenhouses are less energy efficient compared to an attached structure. Freestanding greenhouses are also less convenient to access because the gardener must go outside to enter the greenhouse.
Location of the Greenhouse
Many gardeners believe that a greenhouse should always be located facing south so it receives the most light possible. However, this is not always the best location for a greenhouse. Although the southern exposure will receive the most light, the truth is that most plants do not need that much light and, in some ways, a southern exposure can be counterproductive. During the summer months, a south facing greenhouse can easily get too hot and require a shade cloth to help protect the plants. An overheating greenhouse can hinder plant growth and be a nightmare for the grower. For most hobbyist applications, a greenhouse with western exposure is the way to go. Think “west is the best”. This is not to say that other orientations will not work. In fact, an eastern exposure will work just fine for most plants. A northern exposure may be too shady for any tropical varieties and is the only orientation that should be avoided if possible. Since virtually any orientation will work, greenhouse hobbyists should choose a location that will best complement the home or garden. Just remember that greenhouses do not need to be exposed to the maximum amount of light at all times. In fact, most horticulturists will want sunnier and shadier locations in their greenhouses to accommodate the needs of the various plant varieties.
For more information, please visit ArcadiaGlasshouse.com.
A Quick Guide to Greenhouse Structure and Frame Materials
There are several frame types being used to construct greenhouses. And Depending upon your needs some are better than others. The primary materials are galvanized steel, aluminum, PVC, fiberglass and wood.
Steel is one type of framework used on kits. It is strong, and galvanized steel will be rust resistant, but in time will rust a bit. Because of the weight, it will cost more to ship than other materials. Galvanized steel tends to be used on the lower end greenhouse kits, but it can be found on the more expensive ones too.
Aluminum is strong, will not rust and is lightweight. Round or square tubing is used, depending upon the covering material that is being used. Square tubing is available from building supply stores and this material could be used to construct a greenhouse frame. Drilling holes in it is fairly easy, so fiberglass panels or polycarbonate sheets could be fastened to the structure.
PVC pipe can be used to construct a Quonset type greenhouse frame. It is readily available, inexpensive and easy to work with. Up to one inch diameter can be bent to form hoops over which Polyethylene film can be stretched. Ends can be constructed from either plywood or fiberglass sheets. Fiberglass sheets can also be screwed to the hoops to form a cover over the frame.
Treated wood can also be used to construct a greenhouse. If you are do-it-yourself grower, this type of structure can be a bit harder to build. Just about any type of covering could be installed over a wood frame. It is strong enough for glass, Polyethylene films can be stapled to it and polycarbonate or fiberglass sheets can be screwed to it. Wood is the most versatile material available for a greenhouse structure. Besides pressure treated lumber, cedar and redwood can also be used for greenhouse construction. Both are lightweight and strong. Redwood is the most readily available and tends to be used in high end kits. Greenhouses constructed from redwood are both attractive and long lasting.
Fiberglass tubing is also used as a greenhouse framing material. An advantage to this material is that it will not conduct heat or cold easily, thus helping keep heat in and cold out.
Reasons #9 & #10 of the Top 10 Reasons to Build Your Own Greenhouse
Beat the Cost of Grocery Store Produce
One of the best reasons for a greenhouse of your own is to beat the escalating price of food. For a family of three, a greenhouse will pay for itself in a year or two. No more multiple dollars per pound for produce that you can grow in your own backyard.
Self-Reliance and Independence
As consumers, we are ever more dependent on jobs, fuel, utility companies and government. A greenhouse of your own helps you become independent and self-reliant in one of the most important areas of life — keeping you and your family fed.
Reasons #7 & #8 of the Top 10 Reasons to Build Your Own Greenhouse
Reason #7 – Get Out of the Wind and Harsh Weather
Greenhouses shield you and your plants from the damaging effects of a storm that might bring high winds, driving rains and hail or freezing weather with ice and snow. It also protects your plants from the constant drying effects of winds in more arid environments.
Reason #8 – Garden Year Round
In most places across the country, the sheltered environment of a greenhouse provides enough protection for growing vegetables year round. Even when temperatures drop into the single digits, many cold tolerant vegetable crops can survive just fine.
Reasons #5 & #6 of the Top 10 Reasons to Build Your Own Greenhouse
Reason #5 – Extend the Season
Get started earlier than normal and garden longer than your normal summer season. Unless you are growing plants that are very temperature sensitive, and your environment is harsh, you should be able to count on nearly two months head start and two months extended growing season, all with no supplemental heat.
Reason #6 – Create a Warm and Humid Environment
Plants love warmth and humidity. They thrive in it. A greenhouse allows you to easily capture and maintain an environment of warmth and humidity.
Reasons #3 & #4 of the Top 10 Reasons to Build Your Own Greenhouse
Reason #3 – Choose Your Own Design
A homemade greenhouse provides you the opportunity to design it yourself. It can be as wide, as long, as tall and as strong as you need it to be. Need another door or vent? Just put that into your plan. You’re not stuck with someone else’ design.
Reason #4 – Save Money on Materials and Labor
If you build your own greenhouse, you save more than half the cost of a kit and all the labor costs associated with having it assembled.
Reason #2 of the Top 10 Reasons to Build Your Own Greenhouse
Reason #2 – A Greenhouse Allows you to Have a Designated Spot for Gardening
It provides a home for special accessories, tools and supplies necessary for starting seeds, transplanting, growing, harvesting, cleaning and preparing vegetables and cut flowers.
Reason #1 of the Top 10 Reasons to Build Your Own Greenhouse
Garden & Greenhouse contributing editor Clair Schwan has developed a list of the top 10 reasons to build your own greenhouse.
Reason number 1 is Multiple Purposes
A greenhouse is great for growing fresh organic vegetables, you can also use it to grow flowers, house plants, bulb plants and seedlings of all types. Change what your focus is each year or mix it up as you like.