A few years ago, through the countryside of Bulgaria, I noticed how strikingly similar the landscape was to that of central Virginia. I also noticed that nearly every home had a garden plot, a grape arbor, and a cold frame of some sort. It made me realize how ancient and universal the practice of using cold frames is.
A cold frame is a simple structure that utilizes solar energy and insulation to create a microclimate within your garden. For those of you who have harvested and eaten a salad of fresh greens in February or have flowers blooming well past frost, you know the attraction of using cold frames. You also know how easy they are to make and use.
Although we have a greenhouse on our farm, space is always limited, so we rely heavily, especially in spring and fall, on our cold frames to overwinter plants, extend the growing season, start seeds, and harden off plants.
If you’re not ready for a gardening year to end the first winter of the season, you may also be prepared for a cold situation. This simple bottomless box with removable glass or plastic cover protects the plant inside from too low temperatures, the wind, snow, and rain. By doing so, it creates a microclimate that is a warm half zone of your garden. My garden might be in Maine, but the plants in the cold frame I thought they were in New Jersey. A cold frame in New Jersey provides Georgia weather. The result is a harvest of fresh vegetables throughout the winter.
With a cold frame like this, you can grow greens and other cool-season vegetables right through the winter.