If you’ve ever wished you could have fresh lettuce, radishes, or spinach all winter long, here is some information that will make it possible. You have several options for mini-greenhouses, or cold frames, and the ability to grow cold tolerant vegetables all winter on the south side of your garden.
Vegetables – Here are some cold-hearty crops to grow in your winter garden: onions, garlic, peas, red oak leaf lettuce, tatsoi, perpetual spinach, mache, kale, swiss chard, napoli carrots, and radishes. http://blessmyweeds.com/best-cold-hearty-crops-for-winter/
Straw Bale Coldframe – This method uses straw bales for the walls of the coldframe and an old window or plastic for the top. One layer of straw bales is sufficient, placing one on the ends and two or more on the front and back, depending on the size or sizes of your windows. You can use more than one window, but them together where they meet. You will have to remove them to access the vegetables. https://sunstonefarmandlearn.com/2010/02/07/strawbale-cold-frames/
Cloche – Almost anything can serve as a cloche, or cover, from an upturned five-gallon water bottle with the bottom cut off to the most expensive purchased one. Glass will absorb the most heat from the sun, but you can also buy cloth or plastic ones.
Mini Polytunnel (AKS Hoop House) – Here you can use the raised beds from your summer garden and put a top on them. PVC pipe is cut large enough to stretch from one side of the frame to another and high enough to allow room for the plants. Insert the overhead PVC pipes (or hoops) into clamps or other PVC pipes inserted into the ground inside the edges of the frame. Cover the hoops with plastic. You can also make a frame, attach the plastic to the frame, and hinge it to one end or side of your raised bed. http://yearroundveggiegardener.blogspot.com/2012/02/mini-hoop-tunnels-in-summer.html
Cold Frame – This is a three or four-sided box, made from any number of materials, with the back slightly higher than the front to form a slanted box, and topped with plastic or old windows. You can also be successful with windows on top of your raised beds.
Greenhouse – Whether a small mini, or a full greenhouse, this is the ultimate in winter, spring, and fall gardening projects. Build one out of 2X4s or PVC pipe, or cattle panels, and plastic, buy an inexpensive one, or invest in a larger greenhouse. Overwinter outdoor plants and pots, start seeds in spring, and grow vegetables for the kitchen in winter. https://www.apieceofrainbow.com/21-amazing-diy-greenhouses/