Growing Cold-Hardy Vegetables
Is Cold Weather Gardening for You?
Reading Time: 5 minutes
By Anita B. Stone — Many of us put our gardens to bed once winter arrives. However, by using an abundance of strategies and knowing which cold-hardy vegetables to plant, we can harvest food, even in snow-driven territories where temperatures may drop to zero degrees F — areas where it was often believed that food could not grow. Of course, major challenges have to be addressed and overcome, such as sudden temperature drops, extreme weather conditions, including strong winds, ice, heavy snow, and low light levels. In cold climates, there are not as many options regarding choices for planting as are available in warmer regions, but the limitations of cold weather can be overcome if you know and can implement solutions that work in your part of the country. For instance, being knowledgeable about when to plant is imperative for plant survival. Root systems need to develop before the ground becoming frozen. Although that time varies, for many areas, it’s during August.
For vegetables to survive in very cold weather, planning for protection from the elements is necessary and requires prior effort. Plant protection can take the form of mulch, cold frames, straw banks, cloches, or fallen leaves, depending on anticipated temperature ranges in your location. A hoop frame of poly pipe, bamboo, or natural tree branches can be erected and covered with a see-through plastic for insulation, depending on how long the plants must stay covered. An extra layer of single-skinned plastic between plants and soil will reduce the rate at which heat is escaping.
Consider heat mats, windbreak hedging, and belt planters. Some eco-friendly heating solutions to consider are a hotbed, in which composting manure and carbon materials gently heat plants from below, piped hot water heating with water warmed by a wood-fired boiler, solar power, or fans pumping through a network of pipes under the soil. The soil collects the energy which is then pumped back into the space to keep it warmer. Other protective shelters can be prepared, such as a sunken greenhouse or a greenhouse made with straw bales or adobe on the northern side. Lean-to structures, cold frames, or high tunnel designs can maximize light and heat from the sun. Generally, it’s best to maximize southern exposure in the winter, but increase shade during the summer.
Another factor to bear in mind is the use of dense material with a high thermal mass for protective shields. High thermal mass substances, such as logs, store heat during the day and release it slowly at night. Brick, earth, clay, and ceramic material provide insulation from deep freezes and protect crops from extreme temperatures. Without these precautions, lengthy, deep freezes will cause damage unless sheltering protocols are followed because, as the soil freezes and becomes solid, plant cells will burst and crops will die. Additionally, water must be collected and stored for winter crops before temperatures remain below freezing. Spring rain can be directed into rain barrels that can be insulated in much the same way as plants or by being placed in protected sites.
Certain snow-hardy vegetables can withstand cold temperatures much better than others. For starters, planting heirloom seeds or plants gives the best chances of success. These vegetables have been around for many years, have been genetically pre-selected through natural processes, and have proven to yield produce even during the coldest months of winter.
Greens are fantastic cold-hardy vegetables. It’s hard to beat kale. In my garden, in the Piedmont of North Carolina, kale leaves have lasted, unprotected, through the entire winter, and have yielded three timely crops. The popular King Kale, which not only endures cold and frost but becomes more flavorful once cold weather sets in, also thrives during cold winters. Russian Kale deserves recognition for growing well during the winter months, not to mention their service keeping Russian farmers in the past from starving during that country’s harsh winters.
Another super tolerant green is spinach, a plant whose leaves may die with the cold, but the plant itself can survive and grow new leaves in early spring. A successful species to plant is savoy or any kind with wrinkled leaves.
Collards, a staple southern-grown vegetable is surprisingly freeze-tolerant. Try the Georgia Southern Creole variety or Blue Max for cold northern winters. Blue Max offers high yields that can survive temperatures down to zero degrees F.
Most homesteaders grow Swiss chard during the spring and summer months. For winter growth, it is best to select the green and white varieties. This chard does not require protection unless the temperature drops below 15 degrees F. If such cold is expected, protect the chard with a covering of mulch and it will live through the winter and give extra pleasure by re-growing in the spring.
Lettuce is an all-year and all-time favorite, with several varieties to choose from. It is best to select the young plants, which tend to tolerate cold temperatures rather than the mature ones. Keep lettuce protected with cold frames, hoops, or tunnels. It can survive temperatures down to 10 degrees F and, if covered with mulch layers, can remain viable down to even zero degrees F, depending on the variety.
Another group of vegetables also quite hardy and not bothered by winter cold are leeks, such as Bleu de Slaise. Parsnips, though a bit finicky, actually prefers snow, which makes them taste sweeter. Growing cabbage during the winter does well. The most successful cabbages are the wrinkled leaf kinds which fare better than flat-leafed varieties. Cabbage needs to be planted in late summer to be ready to harvest in the winter.
Similar to some vegetables mentioned, turnips gain sugar with the cold but become less spicy. Turnips require protection from extreme temperatures, so a cold frame or heavy mulching that covers the roots is advised.
Homesteaders are not limited to cold weather plants. Many other vegetables can be added to the winter season, such as arugula, onions, rhubarb, rutabaga, Brussels sprouts, and scallions. If you enjoy plants of the onion family, be sure to create layers of protection so these vegetables can survive under the snow.
Though not covered here, many herbs can withstand and survive cold winter climates, but that would be another fascinating story.
What a wonderful way to continue heart-healthy nourishment all year by having grown fresh winter vegetables and being able to harvest them for yourself and your family. Remember, that while many of these vegetables improve their flavor once frost strikes, most can still be damaged by prolonged deep freezes if not properly protected.
Hopefully, some of these ideas will encourage and inspire anyone to raise winter crops, which will later allow you to wander out, brave the cold, and harvest fresh produce without having to drive through the snow and ice to obtain vegetables for your winter table.
What are your favorite cold-hardy vegetables to grow? We would love to hear from you in the comments below!
Originally published in Countryside September/October 2021 and regularly vetted for accuracy.