Kale: growing from seed, planting out and harvesting all winter

Kale sown in June gives leaves from September until spring. Sowing dates, planting out, picking leaf by leaf and protection from pests.

In brief: For a winter harvest, kale (curly kale) is sown from late May to mid-June, planted in the bed at a spacing of around 50 × 50 cm and picked gradually from September until spring. Pick the lower leaves and let the top keep growing. After the first frosts the leaves become tenderer and sweeter.

Latin name	Brassica oleracea var. sabellica, Brassicaceae
Sowing for a winter harvest	late May to mid-June, depth 1 cm
Germination	5–10 days
Spacing	40–60 × 50 cm depending on the variety
Harvest	September to March, leaf by leaf as needed
Soil	loamy, rich, pH 6.5–7.5, first-year (freshly manured) bed

Kale is one of the few vegetables you can harvest in January straight from a snow-covered bed. It needs no greenhouse or complicated care, just the right sowing date and a little protection from caterpillars and whitefly. A single plant gives leaves all winter, so six to ten plants are enough for a family of four.

Below you will find when and how to sow kale, how to plant it out so that it survives wind and frost, how to harvest so that it keeps growing, and what to do when white flies or holes appear on the leaves.

What kale is and how it differs from other brassicas

Kale, also called curly kale, belongs to the same species as cabbage, kohlrabi and broccoli. Unlike them, it forms neither a head nor a rosette, but a tall stalk with a loose tuft of leaves. It is a biennial plant: in the first year it grows leaves, and in the second spring it flowers and sets seed. In the garden we grow it only for its leaves, that is, for one season.

Several types now appear in shops, differing in leaf shape and flavour:

Type	Leaf	Height	Suitable for
curly green (Czech varieties Kadet, Kapral)	strongly curled, dark green	40–90 cm	braising, soups, chips, winter harvest
Tuscan (cavolo nero)	narrow, blistered, blue-green	60–90 cm	Italian cooking, braising, soups
red and purple	flat to curly, coloured veins	50–80 cm	raw salads from young leaves, decoration of the bed
baby leaf	young leaves of any type	harvested at 10–15 cm	salads and smoothies, growing in a window box

For a winter harvest in Czech conditions, curly varieties are the most reliable. They have a firmer leaf that tolerates frost and wind better. The Tuscan type has a milder flavour but suffers sooner in a hard winter with bare frost.

When to sow kale

The sowing date decides when you will harvest. Kale sown in spring does grow quickly, but by winter it ages and becomes woody, and in summer it is attacked most by caterpillars and aphids. For a winter harvest, late sowing is better.

Main sowing for autumn and winter: from late May to mid-June directly in the bed, or two weeks earlier in a seed tray.
Summer harvest: raise seedlings from March on a windowsill and plant out in April to May.
Baby leaf: small batches every 2–3 weeks from April to August in a window box, or dense rows in the bed.

Raising seedlings step by step

Fill a seed tray or dish with seed-sowing compost and firm it down lightly.
Sow the seeds 1 cm deep, 2 seeds per cell in a seed tray.
Keep at 15–20 °C in the light. The seeds emerge in 5–10 days.
After emergence, leave only the stronger seedling in each cell and lower the temperature to 12–16 °C so that the seedlings do not become leggy.
After 5–6 weeks, when they have 4–6 true leaves, harden them off outdoors for a week and then plant out.

With direct sowing in the bed, place 2–3 seeds at each spot and later leave the strongest plant. General principles for spring sowings are described in the article Spring sowing of vegetables.

Planting out and site

Kale wants sun or light partial shade and deep, rich loamy soil that does not dry out in summer. It belongs in the first-year bed, that is, a bed enriched with compost. In light sandy soil it grows, but the leaves are smaller and tougher.

Plant brassicas in the same place no sooner than after 4 years. Otherwise clubroot builds up in the soil, a disease that cannot be cured and survives in the soil for many years. A pH above 7 also helps, which is why acid soils are limed before planting. Rotation and feeding are covered in more detail in the guide to brassica vegetables.

Spacing: 50 × 50 cm, compact varieties 40 cm, tall ones up to 60 cm.
Depth: plant seedlings slightly deeper, up to the first leaves, and firm the soil around them well. Kale in loose soil flops in the autumn wind.
Watering after planting: generously; in dry weather every other day for the first two weeks.

Care during summer and autumn

Kale needs the most water in summer, when it grows quickly. In dry weather water generously once or twice a week at the roots, not over the leaves. A mulch of cut grass or straw retains moisture and suppresses weeds.

Feed moderately. Compost when preparing the bed and one feed with nitrogen in July are enough. An overfed plant has soft, watery leaves that tolerate frost less well and attract aphids. From September do not feed any more; the plant should harden off for winter. General doses for vegetables are summarised in the article Nutrition and feeding of vegetables.

When the stalk grows taller than 50 cm, earth soil up around it. Tie tall varieties in a windy spot to a stake, otherwise the autumn gale will uproot them, roots and all.

Harvest: how to pick so that kale keeps growing

You can start picking the first leaves roughly 8–10 weeks after planting out, as soon as the plant has 10–12 leaves. The main harvest begins in September and lasts all winter until March.

Always pick the lower and middle leaves, snapping them downwards at the stalk.
Leave the top of the plant and the youngest leaves in the centre; the plant keeps growing from them.
Take 3–5 leaves from a plant at a time, then give it a week or two.
Remove yellowed and damaged leaves regularly; they are a refuge for aphids and whitefly.
In frost do not pick frozen leaves. Wait until they thaw, otherwise they turn mushy after thawing.

After the first frosts kale tastes sweeter and milder. In the cold the plant accumulates sugars in the leaves, which act as natural protection against freezing. Ordinary varieties tolerate frost around −10 °C unharmed, and hardy curly types even more.

In the spring of the second year kale sends up flower stalks. As long as the buds are closed, they can be prepared much like broccoli. Then pull the plant up; the leaves will already have turned bitter and tough.

Pests and diseases: what threatens kale most

Problem	How to recognise it	What to do
cabbage white caterpillars	eaten leaves, green caterpillars and droppings on the undersides of leaves, July to September	protective netting or fleece from planting out, check leaf undersides and collect the eggs
cabbage whitefly	tiny white flies under the leaves, sticky leaves, autumn	remove lower leaves, wash heavily infested leaves before eating, do not plant densely
cabbage aphid	grey waxy colonies in the centre of the plant and on the undersides of leaves	spray off with water, remove infested leaves, do not overfeed with nitrogen
flea beetles	tiny round holes in the leaves of young plants	cover young plants with fleece, water in dry weather
clubroot	plants wilt, galls on the roots	crop rotation after 4 or more years, liming, burn infected plants and do not compost them

The most effective prevention is mechanical: white horticultural fleece or fine netting stretched over hoops straight after planting out. The butterflies then have nowhere to lay their eggs. More about whiteflies and aphids can be found in the article Familiar pests: whiteflies, aphids and spider mites.

Kale in a pot and on a balcony

Compact varieties can cope with a container too. Allow a volume of at least 15–20 litres per plant and a depth of 30 cm. In a window box it is better to grow kale as baby leaf: sow more densely, cut the leaves at a height of 10–15 cm and repeat the sowing every 2–3 weeks.

For winter, move containers close to the wall of the house. Unlike in a bed, the roots in them freeze through, and in hard frost the plant may dry out.

How to use kale in the kitchen

With older leaves, cut out the tough central rib and tear up the leaf itself. Young leaves can be eaten raw in a salad; older ones are suited to braising with onion and garlic, soups, pulse dishes or baking. Chips are popular: massage torn leaves with a drop of oil and salt and dry them in the oven at 120–140 °C until crisp.

Freshly picked leaves keep in the fridge in a bag for 4–5 days. For longer, blanch them for 2 minutes, cool them and freeze.

Frequently asked questions

When is kale sown?

For a winter harvest from late May to mid-June directly in the bed, or two weeks earlier in a seed tray. For a summer harvest, seedlings are raised from March and planted out in April to May.

How should kale be harvested so that it keeps growing?

Snap off the lower leaves and leave the top with the young leaves to grow. Take 3–5 leaves from a plant at a time, then let it regrow for a week or two.

Does kale survive the winter in the bed?

Yes. Ordinary varieties tolerate frost around −10 °C and can be picked until March. After frost the leaves become tenderer. In containers the risk of freezing is greater, because the roots freeze through.

Why does my kale have white flies on the leaves?

This is cabbage whitefly, which appears on kale mainly in autumn. Remove the infested lower leaves and do not plant densely. Wash the leaves thoroughly before preparing them.

Can I grow kale in a window box?

Yes, best as baby leaf. Sow more densely and cut the young leaves at a height of 10–15 cm. For a full-grown plant you need a container of at least 15–20 litres.

What is the difference between kale and curly kale?

None. Kale is the English name for curly kale. However, non-curly types are also sold as kale, for example Tuscan cavolo nero.

Sources

Updated: 27 September 2026

Author: Jana Vránová, the editorial pen name of the Pěstík.cz team. She writes about the garden, herbs and essential oils. We take safety and dosage information from specialist literature and official sources, which we cite in every article.