Growing crops has traditionally been thought of as an occupation for the warmer months. We plant in the spring and grow through the fall. Our crops change as the seasons progress, but vegetable production tends to halt abruptly with the first frost. There are, however, a number of techniques that can extend your growing seasons well into or all the way through the winter.
One of the easiest ways to prolong your growing season is to select cold hardy crops. Leafy greens offer some very good choices in cold hardy crops. Spinach, kale, chard and collard greens all hold up well in cold weather. They are also chock full of vitamins and minerals that may be hard to come by in the winter months. Here in the Missouri Ozarks, winters are often relatively mild. On our farmstead we have been able to grow collard greens without any special precautions well into January. It is an amazing experience to walk out to the garden on a frosty morning, brush the snow aside, and harvest fresh greens for the evening meal.
Here are some other ideas:
1. Floating row covers.
Floating row covers consist of clear plastic sheeting that is rolled out over row crops. By adding floating row covers to your garden, you can extend the season for fall crops far into the winter. These covers promote heating of the soil throughout the daylight hours and provide some protection from frosts and freezes in the overnight hours. Floating row covers can also be used to jumpstart your spring planting season by providing young plants with an edge against cold nights that could cause them to fail. Row covers are by far the cheapest and easiest of the “structures” that can be incorporated in winter gardening.
Tunnels are another valuable tool in extending your gardening year. Tunnels come in two general varieties, high and low. In either case, they consist of an arched framework covered with clear plastic skin. Ends can be either opened or closed. Tunnels are not true greenhouses, and therefore, don’t provide the same level of protection and control. With careful crop selection, however, you can produce fresh vegetables through most of the winter in all but the coldest climates. Lettuce, spinach, mustard greens, bok choy and cabbage are good choices for winter high tunnel growing.
Last winter we were able to grow all these crops in our 70 x 30 tunnel. We were also able to get tomatoes, started from seed in our dining room window, planted more than a month before field tomatoes were even a remote possibility. Prefabricated tunnels are readily available from a number of manufacturers. If you are of the do-it-yourself mindset, build your own using PVC or steel pipe for the frame. Steel will require a pipe bending tool but will result in a sturdier structure. In either case, the frame is then covered with clear plastic sheeting. A tunnel can also be used to start your garden early, removing the plastic cover when the warmer months usher in the traditional growing season.
Greenhouses are a more permanent, and therefore more expensive, option for winter gardening. Greenhouses provide more insulation and environmental control than tunnels. For best results, heating is required, but heating involves an energy output which raises the cost of running greenhouses. Our greenhouse is a small affair that we use primarily for starting plants in late winter or early spring. Small greenhouses can be easily and fairly inexpensively heated with portable heaters, or with a small wood stove. I am intrigued with the idea of incorporating a small rocket stove in our green house. This kind of wood burner is extremely efficient and is used to heat a thermal mass. This thermal mass provides radiant heating even after your fire has burned out. Heated greenhouses eliminate the seasonality of gardening, but they are expensive to build and to heat. They also require a permanent space which becomes unavailable for other uses.
4. Cold frames.
Cold frames are my favorite choice for winter gardening. Cold frames consist of a “bottomless box with a sky light.” A cold frame is built with a slanted top, oriented to take advantage of the low winter sun. The frame is built out of 2x lumber. The frame should be about 12 inches high at the back and eight inches high at the front. A hinged top can be made from a variety of materials such as old windows, sliding glass doors, shower doors, plastic sheeting, or any number of recycled materials. Let your imagination be your guide. Cold frames can provide you with fresh salads throughout the winter months in most climates. Spinach, leeks, scallions, carrots and a wide variety of greens are good choices for cold frame gardening. One interesting crop that does well in cold frames is miner’s lettuce. Miner’s lettuce takes its name from the California gold rush; it was the only salad in town for many 49ers out on their claims. It occurs naturally from southern Alaska to Central America. This leafy vegetable resembles spinach in taste, is an excellent source of vitamin C, and thrives in cold frames all winter. Cold frames are simple, cost effective, and easy to build. They produce a lot of food in a very small space.
5. Indoor gardening.
Don’t underestimate the value of indoor gardening through the winter months. South facing windows can readily be utilized as a year-round home for an herb garden. Herbs add flavor and nutritional value to your meals. Fresh cilantro from the window garden will transform a bland meal into a culinary fiesta. A bit of oregano and a pinch of basil turns a can of stewed tomatoes into gourmet spaghetti sauce. There are many herbs with medicinal value, as well. The same oregano that is the backbone of a good sauce will also boost your immune system and help you to fight off colds. Sprouting is seldom thought of as a method of indoor gardening, but it produces a very healthy and very tasty brand of produce. The act of sprouting seeds and grains increases nutrients by 50 to 400 percent. Allowing sprouts to continue growing will produce micro-greens, another very nutritious food source.
How you choose to extend your gardening season into the winter will be influenced by many things. Considerations will include space, climate and financial resources. As always, do your homework first. Evaluate your available space. Consult an almanac for climate information. Set your budget. Develop your infrastructure. Choose your crops. Then, all that will be left to do is get ready for a long winter of fresh vegetables.