COLD FRAME GARDENING
Carl White, Greenhouse Specialist
Gardeners often think in terms of gardening within the limits of last frost to first frost. This would normally constitute the spring, summer and fall months for our growing season, but what about the cool weather plants and vegetables we would love to have from our own gardens during the winter months?
Vegetables possible include: radishes, leeks, carrots, arugula, lettuce(s), spinach, Swiss chard (Bright Lights), Red Russian Winter Kale, beet greens, and turnips, to name a few. Intermittent harvesting of tender new growth makes some wonderful additions as microgreens as salad. Leaf lettuce is undoubtedly the best crop to grow. It grows rapidly and abundantly in a cold frame. And, there's nothing like fresh, nutritious greens, picked from your own garden during cold winter weather. Spinach is also an excellent green to grow. Other crops that grow exceptional well in cold frames or hot beds are green onions, radishes, and chard, round or little finger carrots, endive and other greens. As you become more familiar with using your cold frame/hot bed, you will undoubtedly want to experiment with other vegetables as well. It is amazing to realize that most of these plants will survive snow and continue producing crops.
Enter the cold frame garden structure: the best location for your cold frame would be a south-facing, sunny spot that best offers some protection from the north winter winds. Ideally, the cold frame would get mid-morning to mid-afternoon sun and can be established permanently in the garden or made portable to remove for summer gardening.
Normally a wooden structure, anchored in the ground below ground level is preferred. You would want to enhance the soil in the cold frame to provide enriched fertile soil. The soil enhancements added such as: compost, humus, barnyard fertilizer (but is better composted), cornmeal (which is a much-discussed topic at present), wettable Sulphur to increase soil acidity, and mulch. Many gardeners will add drip irrigation to conserve water and to all this, a very fertile and protected growing environment.
The cold frame box effect is further protected against the weather elements by addition of a lid. This lid can be raised for air circulation and working in the bed, then lowered to insulate against winds and cold or adverse weather. The sides of the box are normally wooden, but the lid is made of glass panels, old windows, polyethylene sheeting or polycarbonate. All these will allow sunlight to penetrate to the growing material adding warmth and light for photosynthesis. It is necessary that the covering material be clear, or in the case of polycarbonate, opaque but admitting sunlight. Be sure that the lid is high enough to accommodate the growing height of the plants.
Planting the late fall and winter crops takes a bit of planning. Seeds are to be sown in late summer or early fall to be established before cold weather, lettuce being one crop that germinates better in cooler soil than warm. A southern exposure provides sunlight to reach the plants and also warms the earth for protection when experiencing freezing temperatures. At such adverse times, protection at night can be accomplished with a cover of some protective material thrown over the cold frame which is soon removed to gain sunlight when applicable.
For more information contact the Texas AgriLife Extension Office, Ector County 432-498-4071, or Midland, at 432-686-4700. Don't forget, new Master Gardener classes start in January!