Garden & Greenhouse


Garden & Greenhouse Cover Story – Greenhouse Megastore Cold Frames

Posted January 30th, 2018 by Eric Hopper in ,

A cold frame greenhouse may be one of the most valuable tools used by a horticulturist. The term “cold frame” refers to the fact that the greenhouse is not heated. Historically, cold frame greenhouses were built to be used in conjunction with a heated greenhouse. In many cases, they were built adjacent to the heated greenhouse. This allowed the seeds to be germinated in the heated greenhouse and then moved to the cold frame greenhouse to be “hardened-off” before being planted outdoors.

There are many different styles and sizes of cold frame greenhouses, but each serves a similar purpose: to create a microclimate that shelters plants from the wind and extreme cold. In geographical locations with cold winters, a cold frame enables a horticulturist to start his or her plants earlier in the spring and then keep them longer in the fall. Simply put, using a cold frame greenhouse can help a gardener extend his or her growing season. Some growers, depending on their geographical locations, use cold frames throughout the winter to either protect dormant plants until spring or to continue harvesting root vegetables and cold tolerant greens.

Another advantage of a cold frame greenhouse is being able to grow, harvest and bring particular crops to market earlier than normal. The soil and plants contained within a cold frame greenhouse will be kept approximately 5-10 degrees warmer than the ambient outdoor temperature. This usually allows a gardener to start the acclimation process a couple of weeks before the area’s average last frost date. Because cold frames allow a horticulturist to start their crops earlier, it is possible to harvest the vegetable crops ahead of the normal season. During this time, the normally out-of-season vegetables are more expensive and a grower is able to capitalize on the higher prices.

Acclimating (Hardening Off)

In order to properly acclimate young plants to outdoor conditions, the plants must be slowly exposed to their future environment. A cold frame greenhouse works great for keeping young plants sheltered, while giving them a “taste” of outdoor life. The acclimation process, commonly referred to as hardening off, reduces the chance of transplant shock and thickens the cuticle (the waxy protective covering on the leaf’s surface) which reduces the amount of water the plant will transpire.

Plants started in a heated greenhouse or purchased at a nursery can be placed directly into a cold frame for acclimation. Generally speaking, cool-season plants can be started earlier, while most warm-season plants can begin the acclimation process around two weeks prior to the average last frost date. When first introducing the young plants to direct sunlight, a small section of shade cloth can be used to limit exposure. Each day the gardener can remove the shade cloth for longer periods of time until the plants are acclimated. Most plant varieties will be fully acclimated within 7-14 days from when they are first placed in a cold frame greenhouse. Once fully acclimated, the plants can either be planted into the ground or, if the cold frame is large enough to house them, remain in the greenhouse for the growing season. In order to combat excessive heat, cold frames that house crops throughout the summer will need to be opened up or ventilated with motorized fans on hot days. Most hoop houses and side-walled cold frames allow a horticulturist to raise or remove part of the glazing material to increase ventilation and reduce heat build-up.

Many commercial and hobbyists use cold frame greenhouses as their primary greenhouses. Cold frame greenhouses offer many of the same benefits as traditional greenhouses, but are generally less expensive and easier to build. Depending on a gardener’s location, a cold frame greenhouse may not require the same building permits as other greenhouse structures. Always be sure to check with local agencies to see what codes and permits apply.

Cold Frame Maintenance

Cold frames are great, but they are not a “set it and forget it” structure. Unfortunately, there is a little bit of work required to ensure a cold frame works for you and not against you. Solar energy is a very powerful force. It is very important to open a cold frame on warm, sunny days to release trapped heat and bring in fresh air. Growers using cold frames must be very aware of the weather conditions. Even late into the fall, plants can be burned by trapped solar energy on a sunny day. Another consideration is how the microclimate of a cold frame greenhouse can be inviting to unwanted guests. A cold frame’s warmth and protection can be a safe haven for insects and other critters. Cold frames that aren’t ventilated properly might get condensation. This will cloud up the glazing material and possibly create an environment for molds or fungi. To retain transparency, it is a good idea to perform routine cleanings. Routine cleanings also reduce the chance of harboring unwanted pathogens.

Greenhouse Megastore

The term “cold frame” is just a general term that refers to an unheated greenhouse structure. That means there are many different sizes and styles of cold frames. It is in a gardener’s best interest to research the different types of greenhouses to find the one that best fits his or her gardening style. Greenhouse Megastore offers a nice variety of cold frame structures, glazes and accessories. Greenhouse Megastore has over 25 years of experience building and selling greenhouses all over the world. With warehouses in Illinois and California, it is able to quickly ship a wide variety of cold frames to any location.

Greenhouse Megastore has become a leading supplier of hobby and commercial greenhouse structures, greenhouse and garden supplies, and much more. The foundation of its success can be attributed to the in-depth level of technical knowledge that only comes from experience in the growing industry. With a top-notch customer service department, the folks at Greenhouse Megastore are dedicated to providing individuals, small businesses and institutions with easily accessible, relevant information to help them achieve their goals. Greenhouse Megastore’s mission is to encourage the horticultural sector by making commercial quality horticultural products available at a price that makes growing plants even more rewarding. From cold frame kits to loads of accessories, Greenhouse Megastore has everything a horticulturist needs to set up a cold frame greenhouse. With sizes ranging from 16’

to 35’ and options in side-wall heights and glazing materials, Greenhouse Megastore is sure to have the right size and style cold frame for any gardener’s operation.

Both commercial growers and hobbyists are reaping the benefits of using a cold frame greenhouse. Whether it is to extend the growing season or to house the plants for their entire life cycles, cold frame greenhouses can increase the overall yield and quality of a crop. They can also help growers bring certain crops to market earlier; making the crops more valuable than they would be otherwise. Cold frame greenhouses create heightened sustainability for many growers; allowing them to become more self-reliant. Instead of relying on a nursery to start seeds or acclimate young plant starts, a horticulturist equipped with a cold frame can do this for themselves. All in all, a cold frame greenhouse is an important tool for just about any horticulturist who wants heightened self-reliance, an increased growing season, and better control over his or her crops. When shopping for a cold frame greenhouse, be sure to check with the experts at Greenhouse Megastore. They have both the knowledge and supplies you’ll need to get growing.

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