Garden Cold Frame Kits - Cool Weather Gardening using a Cold Frame
Garden cold frames can be an inexpensive way to add some months to the front or back end of your gardening season. Cold frames work on the same basic principles as a greenhouse, but are typically much smaller and less expensive. Plus, they don't take up more of your yard space for the garden.
What is A Cold Frame?
A garden cold frame is a box that sits on the ground, and its most common use is to harden off seedlings as they are prepared for the spring garden season. It often looks like a small box, and has plastic or glass windows on the top surface, that capture the solar heat and warm the box. They are often the size of a standard house window frame, and in fact, one of the most popular ways to make a cold frame is to mount a discarded window frame on a box that stands 8 to 24 inches in height above the ground.
They are similar to and are often used in the same way as a garden cloche. Some would consider the distinction to be that a cloche is a temporary structure that is put in place over the seedlings in the ground, while a cold frame is a permanent structure that sits away from the garden and is used more as a mini-greenhouse.
If you are buying a cold frame kit, be sure to pay attention to the type of window covering. Glass is probably the best, but also the most expensive. Some of the cheaper plastics will cloud over time and do a less effective job of warning the frame. Plastic could also be a potential problem if you are planning to use heating elements to warm the frame. Also, look for double glazing which will do a much better job of retaining the warmth of the sun.
If you do choose glass, you can easily find recycled glass to fit your frame and save yourself some dollars.
Temperature Control
Since cold frames are used in cooler months, sometimes you will get an extremely cold night and it may be necessary to add a layer of insulation like a blanket to keep the interior warm. There are a few cold frame kits that have supplemental heating built in to get you through those cold nights, but they do require some way to get electricity out to the garden.
As an extreme measure to keep the box warmer, you can put a heat lamp or light over the box. (We have done this with our pool pump and it works!)
Alternatively, just as with a greenhouse, some days will get too warm and the temperature is typically controlled by lifting the top window to allow the interior to vent. There are even cold frame kits that have thermostatically controlled hinges that will open the vents automatically.
An Atypical Example
You can make a cold frame a fun DIY project too. A friend that lives close by is going to use this old existing structure on their farm land and convert it to a cold frame garden.
