Grow Your Best Winter Crops
How do you plan for a winter harvest? Grow nutritious food across the seasons with these ideas.
Earth tilts on its axis and creates four seasons as we spin around the sun. Thus, we experience cyclical weather patterns, and this tilt inspires diversity across ecosystems. Most farmers focus their efforts around one primary growing season. But gardeners may like to produce food throughout the cold season.
Demand builds for local, seasonal food, and many want to know what winter crops to grow. You, too, can grow fresh vegetables as the weather cools down. The long-trusted Farmer’s Almanac offers timely advice on Growing Vegetables into Fall and Winter.
So you want to know which cool weather crops to grow? It’s not so hard; all you need is some good information and planning. So follow along as we review some valuable techniques, what to cultivate, and when to grow it.
Winter Garden Methods
Choose from several techniques to plan a successful winter garden. Be mindful of your area’s average frost dates, which crops like cool weather, and how long they take to produce. We will also note how some crops get sweeter with cold exposure.
The Farmer’s Almanac provides a Frost Date Calculator. Input your zip code, and it will tell you both spring’s last frost and fall’s first frost in your area. Use this information when you decide on which crops to grow.
Look at spinach as an example. Pick up your package of seeds, and you’ll find it takes at least a month for spinach to produce. For example, my first frost date for Zone 7a is usually October 18th.
With this in mind, I would plant spinach seed no later than September 18th. Iowa State University compiled a practical planting/harvest guide for how long different crops take to fruit.
Johnny’s Seeds offers a helpful guide on plant types and timing for free (no affiliation). Some varieties like kale get sweeter with frost exposure. These plants produce more sugars when frost hits. The sugars act as a protective mechanism, partly because the freezing point of water decreases when you add solutes.
They offer a helpful chart and explanation to calculate logistics for your cool-season garden. It centers around your region’s last 10-hour day and works backward. First, determine the growing time for each crop, and then plant them relative to the final viable day for crop production.
Many early spring varieties work for winter planning as well. High temperatures may cause lettuces to bolt, but a successive planting can give you fall and winter greens. Yet, of course, that’s not the only option for a cool-weather garden.
Commercial farmers apply succession planting to double or triple productivity. I know here in Tennessee, many farmers now incorporate some crop rotation. Repetitious monoculture corn production pulls a lot of nutrition from the soil.
Corn’s planting follows soybeans (legumes), which fixate nitrogen due to rhizobacteria at their roots. A third planting might include a groundcover that prevents erosion between cash crops.
Research from the University of Vermont offers some technical advice. They determined that sorghum-Sudangrass makes an excellent ground cover during the summer. Rye serves the same function during winter. Both prevent soil erosion, aerate soils, suppress weeds, and produce biomass.
Avoid the summer heat by starting your winter veggies indoors. It may be intolerable outside, but your babies do fine under an LED light or in a south-facing window. Plant them outside according to the planting guide, and the Almanac also offers advice to start seed indoors.
You could also extend your season with protective coverings from the frost. Whether a greenhouse, polytunnels, or even a bedsheet, creating pockets of warmer air protects plants from light frost. Yet, you’ll find growing outside more difficult after the last ten-hour day despite the temperature.
Exposure and Flavor
Some crops taste better after a frost. The largest group is Brassicas, and this family includes kale, Brussel sprouts, and winter cabbages. Some taproots like parsnips and alliums like leeks also improve in flavor after frost exposure.
Common knowledge informs us that plants convert sunlight, carbon dioxide, and water into starches. Many species break down stored starches into sugars in response to a cold snap. Metabolizing these sugars “warms the plants,” and it also prevents ice crystal formations.
While you have many varieties that grow well or better with cold, a few stand out. The most cold-tolerant families include Asters, Brassicas, Alliums, Amaranths, and some Apium. So let’s take a look at some cool weather veggies worth planting.
Who knew that lettuces belong to the Daisy/Asteraceae family? Midsummer temps encourage lettuces to bolt, but succession planting for a winter crop keeps you stocked with salad greens. Furthermore, you can enrich soils by rotating crop types in succession.
Find many varieties of cold-hardy lettuce to grow from seed. Seek out heirlooms from community gardens, farmers’ markets, university agricultural extensions, and more. Sustainable Market Farming recommends varieties such as Green Forest, Hyper Red Wave, and Merlot. Direct sow 6–8 weeks before the first frost, around August.
Brassicaceae consists of both mustards and cabbages. By far the most expansive of cold-hardy crops, western-style gardens make full use of them. Kale tops the list, and it’s one to get sweeter from the cold. Sow kale at least 15 weeks before the first frost — in June or July. From Zone 5 towards the equator, you need minimal winter cover, if any.
Curly-leafed kale is the most popular. Enjoy kale throughout the year, and harvest the dark, green leaves. Some varieties will return each season.
Plant your baby-leaf Brassicas 5–6 weeks before the Persephone Period. We mentioned earlier to note the last 10-hour day, and the Persephone Period refers to the time beyond that point. Some examples include mustards, arugula, collards, and bok choy. Collards can tolerate temperature dips to 5°F/-15°C.
Allium means “garlic” in Latin. Amaryllidaceae includes both garlic and onions, and many identify them by their sulfurous smell. Plant garlic in the fall for your winter garden, and it will be ready to harvest by spring.
Leeks are an allium that ripen in the fall to harvest during winter. They thrive in temperatures as low as 20.0°F/-6.7°C, and they will survive seldom dips to 0°F/-17.8°C. Leeks need a long growing season. Start indoors and transplant in spring per the University of Minnesota, Extension.
Garlic and leeks are not your only options. DenGarden provides quality tips on growing winter onions which offer an excellent food source until next year’s main crop. Experiment with different alliums like green onions, shallots, and chives.
Amaranthaceae offers two prime winter vegetables: spinach and chard. Many gardeners find that spinach is easy to grow, and you want to start seed 5–7 weeks before the Persephone Period. Start seeds indoors as spinach doesn’t germinate well in excess heat.
Cold exposure sweetens both spinach and chard. Swiss chard provides color, nutrition, and flavor in the cold months. It survives temps of 15.0°F/-9.4°C without any cover, so include amaranthus in your plan.
The family Apiaceae includes favorites such as carrots, parsnips, and parsley. Like other winter veggies, carrots become pretty sweet. They keep their characteristic orange color, while other orange crops display pallor from the cold. Plant carrots 10–12 weeks before the first frost.
Plant carrots in the fall to harvest next summer called overwintering. You can also plant early enough in the primary season for a winter harvest, but plan to protect their leaves. Grow under covers to protect their tops and warm soil for harvest. Carrots survive temperatures below 15.0°F/-9.4°C.
The spotlight shines on the summer months, but now you know how to grow food year-round. Apply techniques like succession planting, augmented micro-climates, seed-starting, and overwintering.
These methods promise to improve flavor, yields, reliability, and profitability.
Furthermore, we discovered several plant families that perform well during winter months. Kale, spinach, and other brassicas excel, given cold environmental conditions. Several varieties produce in bounty when you take certain precautions — like assorted alliums, carrots, and chard.
Do you have experience growing food during winter? If you have any tips, please leave them in the comments sections below. Thanks for reading.