Kale is the toughest, most forgiving leafy green you can grow: it stands through winter frosts, it crops for months, and its flavour actually improves after a frost. It is also one of the easiest vegetables for a beginner — sow it, thin it, pick it, and it just keeps going.
Kale is a cool-season crop that loves cold weather and hates heat.
Kale at a glance
| Growing factor | What kale need |
|---|---|
| Sun | full sun |
| Soil pH | 6.0–7.5 |
| Days to germination | 7–10 |
| Days to maturity | 50–65 |
| Spacing | 12–18 inches |
| Water needs | moderate |
| Cold tolerance | hardy |
| Family | Brassicaceae |
Starting seeds
This crop can be started indoors or sown direct, and either route works well. Indoors, sow in trays, cells or small pots and expect germination in 7–10 days; direct-sown seed goes into a prepared bed once conditions are right. Starting indoors buys a few weeks of season and steadier germination, while direct sowing is simpler and avoids transplant shock.
Shorter-season gardens in the cooler zones gain the most from starting indoors, while warmer zones can usually direct-sow with confidence. Our seed-starting calculator works out indoor sowing dates from your frost dates. Zones 11–13 are frost-free, so sowing windows there are about heat and rain instead — check your local extension service.
Kale can be started indoors or sown direct, and direct sowing in a well-prepared bed works well. Sow thinly and thin the seedlings to their proper spacing — crowded kale stays small and is more prone to pests. A late summer sowing gives plants that stand through winter, and a spring sowing gives an early summer crop before the heat arrives.
Transplanting and planting out
Kale transplants easily if you start it indoors, and indoor-grown plants give you a head start for an autumn crop. Plant out sturdy seedlings at their full spacing and water them in well. Firm them in firmly, since tall kale plants can rock in winter winds, and a mulch layer helps hold moisture through dry spells.
Space plants 12–18 inches apart — crowding is one of the commonest causes of small harvests. Our plant-spacing calculator works out how many plants fit your bed.
Soil and feeding
Kale grow best in rich, well-drained soil with plenty of organic matter. Dig in compost before planting: it improves heavy soil, helps light soil hold moisture, and feeds the soil life that feeds your plants. Aim for a soil pH of 6.0–7.5 — a simple soil test will tell you where you stand, and garden lime or sulfur can nudge pH up or down over a season, so test before you amend rather than guessing.
Feed lightly and steadily rather than in one heavy dose: too much fast nitrogen late in the season pushes leafy growth at the expense of the part you eat. Our fertiliser calculator works out amounts for your bed size, and the soil-volume calculator tells you how much mix a new bed needs.
Watering
Water needs are moderate: keep the soil evenly moist, watering deeply when the top inch or two dries out. Deep, infrequent watering builds deeper roots than a daily sprinkle.
Water at the base of the plant, in the morning, so the leaves dry quickly and the water reaches the roots. Our watering calculator gives a starting point for your bed size, and the watering schedule generator can build a routine around it. A mulch layer cuts evaporation and keeps moisture even.
Sunlight and temperature
Kale need full sun — a spot that gets sun for most of the day. Our sunlight calculator can check your spot.
This crop is rated hardy for cold tolerance, so it stands up to frost and even light freezes, and it is at its best in the cool seasons. In Zones 11–13, which are frost-free, heat rather than cold is the limit — grow it in the cooler months, with afternoon shade in the hottest weather. Our hardiness-zone finder will confirm your zone, and the frost-date calculator gives you the frost dates to plan around.
Pests and diseases
The pests and diseases most often reported on kale are cabbage worms, aphids, flea beetles, slugs. Healthy, well-watered plants resist attack better than stressed ones, and rotating beds so the Brassicaceae family does not repeat in the same spot helps keep soil-borne problems down.
- Cabbage Worms — small green caterpillars that chew holes in brassica leaves; fine mesh from planting time keeps the butterflies off.
- Aphids — small sap-sucking insects on new growth; wash off with a strong jet of water and encourage ladybirds.
- Flea Beetles — tiny jumping beetles that chew shot-holes in leaves, worst on seedlings; row cover keeps them off young plants.
- Slugs — chew ragged holes in leaves at night; water in the morning so the surface dries by evening.
Inspect plants weekly, especially leaf undersides, and act early. Our pest-identifier helper can help identify what you are seeing.
Companion plants
Good companion plants for kale include:
- Marigolds — their roots discourage some soil pests
- Basil — attracts pollinators
- Onions — their scent is said to confuse pests
- Lettuce — shallow-rooted, fills gaps without competing
Our companion-planting finder can suggest more pairings for your bed plan.
Harvesting
Pick kale leaf by leaf from the outside of the plant, starting with the largest, lowest leaves and working up — the plant keeps producing new leaves from the centre for months. Young leaves are tender enough for salads, while older leaves are best cooked. After a frost the leaves turn sweeter, so the winter pickings are often the best of all.
Expect the crop to be ready about 50–65 days after sowing, though weather and variety shift that window by a week or two either way. Our harvest-date calculator works out your expected harvest date from your sowing date, and the vegetable-yield estimator can estimate how much a bed should produce.
Common problems and fixes
| Problem | Likely cause | Fix |
|---|---|---|
| Plants bolting to flower | hot weather | Kale bolts when it gets hot, so grow it for autumn, winter and spring rather than high summer. |
| Aphids clustering on the leaves | soft, sappy growth in warm weather | Spray aphids off with a strong jet of water and encourage ladybirds. |
| Tough, bitter leaves | leaves left too long or plants under stress | Pick leaves young and regularly, keep the soil moist, and remember that kale tastes best after a frost — summer leaves are always tougher.. |
Plants bolting to flower
Kale bolts when it gets hot, so grow it for autumn, winter and spring rather than high summer.
Aphids clustering on the leaves
Spray aphids off with a strong jet of water and encourage ladybirds.
Tough, bitter leaves
Pick leaves young and regularly, keep the soil moist, and remember that kale tastes best after a frost — summer leaves are always tougher..
Frequently asked questions
When should I plant kale?
Sow once the soil is workable in spring — this crop is rated hardy for cold tolerance, so it can go in early. For zone-specific timing, see zone 3 or zone 6, and check your local extension service for the dates that fit your area.
How long do kale take to grow?
Kale take 50–65 days from sowing to maturity, and seed germinates in 7–10 days. Weather and variety shift the harvest window by a week or two, so judge readiness by look and feel rather than the calendar alone.
How far apart should I plant kale?
Space plants 12–18 inches apart — that is the room a mature plant needs, and crowding means poor airflow and small harvests. Our plant-spacing calculator works out how many fit your bed.
Does kale really taste better after a frost?
Yes — cold weather triggers kale to convert some of its starches into sugars, which is why winter-picked leaves taste noticeably sweeter than summer ones. It is also why kale is one of the few vegetables that is genuinely better grown for winter than for summer.