Cold frames are one of the oldest season-extending tools in gardening. Gardeners have used simple low-cost boxes with a clear lid to trap the sun’s warmth and protect plants from frost. Cold frames can be built from almost anything—scrap lumber, old windows, recycled storm doors, or even straw or hay bales stacked to form the sides with a sheet of plastic or glass on top. Beware that on sunny spring days, temperatures inside can climb quickly, so venting the lid is essential. A cold frame without ventilation can cook tender seedlings faster than frost can kill them.
Growing Home - Cold Frames
