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 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.
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.
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