To get the most food from your survival garden, you will want to grow crops 12 months of the year. But if you live in an area with cold winters, your choice of what to grow is limited by frosts, freezing temperatures, and snowfall. There are several different solutions to this problem.
1. Cold-tolerant Vegetables
The list of crops killed by hard frost, or even light frost, is very long. Fortunately, there are more than a few crops that will tolerate hard frosts and even survive an entire New England winter. Among these are leaf crops and root crops, as well as a few grains.
Kale will survive freezing temperatures and deep snowfall. Like all cold-tolerant crops, kale needs temperatures above freezing to grow, but it will weather very cold temperatures. Kale is a good source of many vitamins, including beta-carotene and the B vitamins. This crop is also relatively high in protein; at 4.28% protein, kale has more protein than cooked rice and more protein than most root crops, such as potato.
Other cold-hardy leaf crops include: lamb’s lettuce, mustard greens, arugula, and turnip greens. Collards are a mid-season leaf crop that is extremely tolerant of cold weather. Spinach is cold hardy, and a number of cultivars of lettuce also survive freezing temperatures. Wild dandelions have edible leaves and edible roots, and are also cold-tolerant.
Many varieties of carrot can survive an entire winter. The roots will continue to grow whenever the weather is above freezing. You can harvest carrots at any size, so a crop planted in fall will provide food throughout the winter. What is left of the crop in spring will complete its growth and provide a spring bounty.
Daikon is also called ‘oriental radish’. It is a cold-tolerant root crop, much larger than the ordinary radish. Parsnips, salsify and scorzonera (black salsify) are also very cold-hardy root crops. Many leaf crops improve in flavor and sweetness once temperatures drop below freezing, and the same is true for some roots, such as parsnip. The freezing temperatures increase the sugar content of the crop.
Brassicas do well in winter weather. Broccoli, cauliflower and cabbage all survive hard frosts. Brussels sprouts offer the advantage of rising above the snow, so that you can find and harvest the sprouts throughout the winter. Even if the snow covers your crop, the plants will generally survive and the food crop can be harvested.
Leeks are also able to survive the entire winter and can be harvested any time that the plant is not frozen solid.
2. Grains that over-winter
Corn (maize) is generally not very cold tolerant. However, certain varieties of flint corn (used for flour) are able to survive hard frosts (but not an entire winter). A cultivar called “Roy’s Calais Flint” has the reputation of having survived repeated hard frosts during the “year without a summer” of 1816.
You can plant winter wheat in the fall, for a spring harvest. However, the crop does not bear any grain in fall or winter, it only survives the winter to finish growing once the weather warms. Rye, triticale, and spelt will also over-winter.
Oats and barley do not survive winter weather. Many other grains and pseudo-grains like quinoa and amaranth do not survive hard frosts.
3. Protect crops with mulch
Root crops tend to do better in freezing temperatures if the roots are protected by a thick layer of mulch. Common mulch materials include: hay, straw, bark mulch, wood chips and even newspapers. Straw works particularly well. A thick layer of several inches will protect root crops from severe winter weather. Mulch also reduces competition from weeds, and helps the soil to retain moisture.
4. Cold Frames
A cold frame is like a mini-greenhouse over a small area of your garden. The typical cold frame is only a few feet wide by several feet long. I have the book Solar Gardening, and it is an excellent resource on extending the growing season through the winter months. It has detailed instruction for building different types of cold frames. A cold frame can be as simple as a piece of sturdy clear plastic, which is shaped like funnel and placed over one plant. Or it can be a wooden structure with a clear plastic top to function like a little greenhouse over several plants.
The purpose of a cold frame is to increase the temperature around the plants, so that they can grow during the day, even in winter months. At night, the plants inevitably freeze again, but daytime temperatures inside the cold frame may be high enough to allow some growth.
Small hoop houses can serve the same purpose as a cold frame. A cold frame is sometimes insulated, but a hoop house is simply a metal hoop stuck into the ground on two sides, with plastic stretched over it. This protects the crop from snow and increase air temperatures around the plants during the day. Hoop houses are less sturdy but also less expensive than cold frames, and they cover a larger area of your garden. They can even be large enough to walk around inside (at which point you basically have a full-blown greenhouse).
5. Start spring crops indoors.
To get a jump on the spring planting season, you can start crops indoors as seedlings several weeks before the weather is warm enough for planting. Florescent or LED lights can substitute for sunlight, or you can use a sunny location near a window indoors. The seedlings will grow with relatively little soil, water, and space. And when you establish a crop from transplanted seedlings, rather than by direct seeding into the soil, you typically will get a higher yield.