It’s always sad when the growing season draws to an end, so we like to try and extend it for as long as possible by using row covers, tunnels, and cold frames. If you have some cool weather crops, such as broccoli, carrots, lettuce, and kale, these devices can be installed before and after the typical growing season (i.e. from March to May and September to December) to keep the veggies coming!
Row covers (or floating row covers) are a great way to reduce frost damage and keep out predators while allowing in water and sun. They are made from knitted high-density polyethylene (HDPE) and are quite simple to install. They can be supported by a framework such as a series of hoops made from wire, re-bar, PVC pipes or electrical conduit, or you could choose to forgo the frame and simply anchor your row cover to the ground. See here for step-by-step instructions for installing your row cover.
Tunnels are similar to row covers but are made from plastic, acting as a small greenhouse over your garden. When constructing it, make sure to use plastic that is suitable for nurseries or greenhouses.
To construct the tunnel you can use the same frame as for a row cover, but then need to cover it with plastic and secure it in place with stones, firewood or other sturdy materials. There are both low and high tunnels depending on your budget and needs, but unless you absolutely need to be able to stand upright in your tunnel, a low tunnel is fine for cold-weather crops. Here is a useful video on how to cover a tunnel, and on how to extend a low tunnel into a high one.
From basic to sophisticated, creative and decorative, there are hundreds of ways to construct a cold frame, each one highly effective in prolonging your growing season. The greatest part about cold frames is that they can often be built using materials that you may have stored away in your shed or basement such as old windows or doors with glass inserts. For vintage inspired designs, check your local antique shop or second-hand stores.
Whether you choose to purchase a model or build one yourself, make sure it provides adequate ventilation for your crops. Like any greenhouse, your cold frames could store a whole lot of heat when it is sunny out; just make sure there is space for some air to pass through!