If you want a vegetable patch that still looks alive in January, kale is the plant for the job. It’s tall, tough and slow-growing, and it keeps giving for weeks or even months when most other crops have finished. Learning how to grow kale in winter is mostly a matter of planning ahead: get the plants established in the warmer months, give them a solid footing, protect them from the few pests that bother them, and then pick a little at a time once the cold arrives.
There’s a bonus, too. Cold weather doesn’t just tolerate kale, it often improves it. Here’s how to get from seed to sweet, frost-kissed leaves.
Why Cold Makes Kale Taste Better
Many gardeners notice that kale picked after a frost tastes milder and sweeter than leaves picked in summer heat. The commonly given explanation is that plants in cold conditions convert some of their stored starches into sugars, which helps protect their cells from freezing. Those extra sugars soften the bitterness you sometimes get from warm-season leaves.
How noticeable this is depends on your variety and your weather. Some kales are naturally sweeter than others, and a mild winter with no hard frosts won’t give you quite the same effect. Taste is also personal, so try a leaf before and after a cold snap and decide for yourself.
Choose a Variety That Suits Your Winter
Kale is a group of related types rather than a single plant, and they differ in hardiness, size and texture.
- Curly kale is the classic, ruffled type. It is generally very hardy and the frilly leaves hold up well in cold weather.
- Lacinato, cavolo nero or Tuscan kale has long, dark, puckered leaves. It is popular for cooking and usually does well in cold, though it may be slightly less tolerant of severe winters than the toughest curly types.
- Red-leaved types such as red Russian are tender and good for salads when young. They often cope well with cold, but check the seed packet for the hardiness of specific varieties.
- Tall, old-fashioned types (sometimes sold as “tree kale” or by heirloom names) can grow very large and last a long time, but they need more space and sometimes staking.
If you live somewhere with very hard winters, look for varieties described as extra hardy and consider a sheltered spot. If your winters are mild, almost any type will carry on, and your main job will be keeping pests in check.
When to Sow and Transplant
Kale grows slowly, so the goal is a sturdy, established plant before growth slows down in the short days of late autumn. Timing depends heavily on your climate, so work backward from your first expected hard frost or from the point when growth stalls in your area.
Sowing seed
- In many temperate climates, sowing from spring to early summer gives plants time to reach a good size before winter. Check your local last-frost and first-frost dates and the guidance on the seed packet.
- In regions with hot summers, a late-summer sowing may be better, because young kale struggles in extreme heat. In very mild-winter areas, sowing in late summer or early autumn can still produce a good winter crop.
- In places with very short growing seasons, you may need to start seed indoors earlier so the plants are big enough before the cold sets in.
You can sow into small pots or a seed bed and move the plants later, or sow directly where they’ll grow. Starting in pots or modules is useful because it keeps young seedlings protected and frees up garden space while an earlier crop finishes.
Transplanting
Move seedlings to their final spot when they have several true leaves and are sturdy, usually after four to six weeks, depending on conditions. Water them well before and after planting. If you buy young plants rather than raising your own, the same rule applies: choose healthy, stocky plants and avoid any that look leggy or yellow.
If planting is late, don’t panic. Late-planted kale may stay smaller and give you a lighter harvest, but it can still produce useful young leaves.
Site, Soil and Spacing
Kale likes a sunny spot, though it tolerates partial shade, especially in warmer climates. In winter, shelter from the strongest winds is helpful, because tall plants can rock in the soil and loosen their roots.
It prefers firm, fertile, well-drained soil. Loose, fluffy soil can lead to wobbly plants, so avoid digging deeply just before planting. If your soil is light and sandy, firm it down by treading gently over it before you plant. If it is heavy clay, improve drainage with well-rotted compost, as waterlogged soil in winter can cause rot.
Kale, like other brassicas, generally prefers soil that isn’t too acidic. If you know your soil is strongly acidic, a soil test can tell you whether adding lime is worthwhile. Avoid liming without testing. Also, try not to plant kale where other brassicas grew recently, since rotating crops over a few years helps limit soil-borne diseases such as clubroot.
How far apart to plant
Spacing depends on the variety. As a general guide:
- Compact or dwarf varieties can go about 30 to 45 cm (12 to 18 in) apart.
- Larger, taller types do better with 45 to 60 cm (18 to 24 in) between plants.
Check your seed packet, as it will give the most accurate advice for your variety. Crowded plants get less light and air, and are more prone to disease, but slightly closer spacing can work if you plan to harvest young leaves.
Plant firmly, with the lower leaves just above the soil. Pressing the soil down around the stem helps anchor the plant. Some gardeners plant slightly deeper than the pot level to improve stability, which works well for leggy seedlings.
Feeding and Watering
Kale is a fairly hungry plant, but you don’t need to overdo it. If your soil was enriched with compost or well-rotted manure before planting, that may be enough to start. For poorer soil, a balanced organic fertilizer at planting helps.
- During active growth in summer and early autumn, a nitrogen-rich feed, such as a general-purpose liquid feed or a top-dressing of compost, supports leafy growth.
- As cold weather arrives, ease off. Too much nitrogen late in the season produces soft, lush growth that is more vulnerable to frost damage and pests.
- Water young plants regularly until they’re established. Established kale is fairly drought tolerant, but it grows best with steady moisture, particularly during dry spells in early autumn.
A layer of mulch around the base helps retain moisture, suppress weeds and insulate the soil, but keep it a little away from the stem to avoid rot.
Pest Control: Cabbage Whites, Pigeons and More
Kale’s long season means it is exposed to a range of pests. The main ones can be managed with a little forethought.
Cabbage white butterflies and caterpillars
These butterflies lay eggs on brassica leaves in summer and early autumn, and the caterpillars can strip a plant quickly. Your best defense is physical protection.
- Cover plants with fine insect mesh or netting as soon as you plant them, making sure the edges are sealed so butterflies can’t sneak in.
- Check the undersides of leaves regularly for clusters of small yellow eggs and squash them or wipe them away.
- Pick off any caterpillars you find.
Caterpillar activity usually drops as temperatures fall, but in mild climates you may need to stay watchful for longer.
Pigeons
Wood pigeons and similar birds can be a real problem in winter, when other food is scarce. They can shred leaves and leave plants badly damaged. Netting is the most reliable solution. Support it on hoops or a frame so it sits clear of the leaves, because birds can peck through netting that rests directly on foliage. Bird-scaring devices may work for a while, but birds often get used to them.
Other things to watch for
- Aphids can hide in curly leaves. Rinse them off with water or rub them off by hand.
- Slugs and snails can nibble young plants, so protect seedlings in particular.
- Whitefly may linger in sheltered spots. Remove heavily infested leaves.
- Clubroot is a soil-borne disease that causes swollen, distorted roots. Crop rotation and good drainage help reduce the risk, and some varieties offer resistance.
Remove yellowing or damaged lower leaves regularly. They can harbor pests and disease, and clearing them improves air circulation.
Winter Care for Tall Plants
Because kale grows tall, it can topple in winter winds and wet soil. Firm the soil around the base after storms, and stake taller plants if needed. Some gardeners draw a little soil up around the stem as an extra anchor.
In very cold climates, a covering of horticultural fleece during the harshest snaps can protect plants, although established kale is often hardy enough to cope without it. Snow can actually act as insulation, but heavy snow may bend or snap stems, so brush it off if it builds up.
How to Harvest Kale Repeatedly
Kale is a “cut and come again” crop, which is part of what makes it so valuable in winter. The key is to harvest in a way that keeps the plant producing.
- Wait until the plant is established. Begin picking when it has plenty of leaves and is growing strongly, generally when the leaves are about the size of your hand.
- Pick from the bottom up. Take the older, outer leaves first, snapping or cutting them close to the main stem.
- Leave the growing tip. The crown at the top continues to produce new leaves. Keep a good rosette of leaves on top so the plant can keep growing.
- Take a few leaves per plant at a time. Spread your picking across several plants rather than stripping one.
- Harvest after frost if you like sweeter leaves, but avoid picking when leaves are frozen solid, since they can be brittle and bruise easily. Wait until they thaw.
Young leaves are the most tender and are good raw in salads. Larger leaves are better cooked, and you can strip out the tougher central rib if it’s fibrous.
Spring and the end of the season
As days lengthen and temperatures rise, kale will eventually try to flower. In many climates this happens in spring. The tender flowering shoots can be picked and eaten much like broccoli, and they are a welcome treat. Once the plant bolts fully, the leaves become tougher and more bitter, and it’s time to pull it up and make space for the next crop.
A Simple Winter Kale Checklist
- Pick a variety that matches your winter severity.
- Sow or transplant early enough for plants to establish before growth slows.
- Plant in firm, fertile, well-drained soil, with generous spacing.
- Feed during active growth, then ease off as cold arrives.
- Net against butterflies and pigeons from the start.
- Firm and stake tall plants against wind.
- Harvest outer leaves little and often, leaving the top intact.
Kale rewards patience. Put in the work early, and you’ll have a dependable supply of nourishing greens for weeks, with leaves that often taste best when the weather is at its coldest.