Cold frames allow gardeners to streth their growing season and nurture plants that are used to warmer climates. They are often rectangular structures with a light-permeable roof that allows sunlight in but protect plants from rain, snow, and wind. Choose a fairly level and well-drained spot to place your cold frame. For extra protection, nestle it against a building, fence or hedge on the north side so that the south-facing frame will still receive the maximum amount of light.