Want to extend your growing season for garden veggies? Consider
these structures to protect vegetables and extend their growing season. For homesteaders who need to feed their family all year long, these are necessary to supplement canned and other stored food with fresh greens. Our ancestors used these techniques to survive.
Cold frames are simple box structures that utilize solar energy and insulation to create a micro climate in your garden. They can be used to extend the growing season beyond the natural frost time, they can be used to grow some cold loving plants during the winter months, to start seeds and to get young plants used to being outside gradually. They can be dug down into the soil a few inches to take advantage of the warm earth. They also need a cover of plexi or glass to allow sunlight to enter and provide both light and solar heat. Cold frames need to have a way for ventilation to let excess heat and humidity escape. When planting in a cold frame be sure to have it in place about two weeks before seeding to warm the soil and enhance germination. Caleb Warnock, author of “Backyard Winter Gardening,” uses them to feed his family green plants during Utah’s bitter winters. His biggest challenge is getting into them when everything is iced up. He uses a claw hammer to tap gently around the box lids. Decisions on insulation will depend on your environment. You can choose from nothing to hay bales to help create a warm place for your plants. Some gardeners use manure and vegetable scraps buried 6-8 inches below the planting soil. As it decomposes this compost adds internal heat to the cold frame. Another gardener uses discarded tires stacked 2 high. The black tires absorb heat during the day warming the soil. Most cold frames are low, so plants that can be harvested a leaf or two at a time like lettuce, kale and Swiss chard work well.
Hoop Houses, also known as high and low tunnel houses, can cover in-ground plants or rows of raised planters. Made from metal, plastic pipe or wood and covered with heavy greenhouse plastic, gardeners can grow vegetables all winter long. Depending on your budget, you can make them tall enough to stand under or removable for access. They are heated by the sun and cooled by the wind. Locate it in the sunniest area of your yard in winter, facing east to west long side to maximize the amount of sun that hits it as the sun arcs through the sky each day. Plant in raised beds or in the ground rather than containers. Pot soil freezes quicker. Also plant in succession to assure crops to harvest all winter. Be sure to keep an eye on the temperature. It should stay under 80ºF. Water only when necessary to minimize plant diseases. Root crops like carrots, beets and radishes grow slowly because of the reduced temperature and daylight, but they will certainly be ready for an early spring harvest if started in the late fall. Hoop houses can also be used to grow heat-tolerant varieties of lettuce during the summer by converting the hoop house into a shade house with shade cloth. Remove the plastic cover and replace with 50% shade cloth. Cool and irrigate with sprinklers.  You can change a zone 5 planting area to zone 8 by making a double hoop house.
Billie Nicholson, Editor