Overview
What kale needs, when it crops, and whether it suits your garden.
If other brassicas have let you down, try kale. There’s no head to form, just steady growth and protection from pigeons and caterpillars. Pick a few lower leaves at a time and a plant keeps giving from autumn through winter into spring, and frost makes the leaves sweeter.
Quick facts
- Botanical name
- Brassica oleracea var. sabellica
- Soil pH
- 6.0 – 6.8
- Feeding
- Moderate feeder
- Hardiness
- Any zone, as an annual
- Time to harvest
- 50 – 60 days
- Height
- Up to 150 cm (59 in)
- Propagation
- Seed
Survives −9 °C
Growing details
- Spacing
- 45 cm (18 in)
- Sowing depth
- 10 mm (⅜ in)
- Frost sensitivity
- Frost hardy
Growing calendar
- Start indoors: March, April
- Sow outdoors: March, April, May, June, July, August
- Transplant: April, May, June, July
- Harvest: January, February, March, April, September, October, November, December
Modules from March (RHS), 5 to 6 weeks before planting out. Spring to early summer; in warm-winter regions, late summer to winter. At 10 to 15 cm (4 to 6 in) tall. Leaves from September through winter to spring; baby leaves sooner.
Is this plant right for you?
- Winter harvests
- Very frost hardy
- Beginner friendly
- Needs pest netting
- Good in pots
- Ornamental
- Cut and come again
Good to know
It stands frost, so it can go out earlier than tender crops.
Before You Grow
Choose curly, Tuscan or red kale, and a sunny spot with firm, fertile soil.
Kale is one of the hardiest leafy vegetables: frost sweetens the leaves rather than harming them.
What you need
Seed or young plants
Curly, Tuscan or red types. See choose your kale.
Modules
For raising sturdy transplants. See sowing.
A sunny bed
With fertile, firm soil not used for brassicas last year. See soil.
Fine insect mesh
On hoops or canes, against pigeons and caterpillars. See protection.
Stakes
For tall plants in exposed winter gardens.
A large pot, optionally
At least 30 cm (12 in) for a compact variety. See containers.
Choose your kale
Kale is a non-heading form of cabbage, and its many varieties differ mainly in leaf shape, colour and hardiness. Many are ornamental as well as good to eat.
Curly kale has frilly green or blue-green leaves: ‘Dwarf Green Curled’ and ‘Vates Blue Curled’ are compact and very hardy; ‘Winterbor’ grows to about 60 cm (2 ft). Curled leaves are harder to wash.
Tuscan kale (‘Cavolo Nero’, lacinato, dinosaur kale) has long, narrow, puckered blue-green leaves on upright plants 60 to 90 cm (2 to 3 ft) tall. The upright leaves stay clean.
Red Russian and Siberian kale belong to a different species (Brassica napus), grown the same way. Their leaves are flat, lobed and tender, with red veins in Red Russian; Siberian is the most cold-hardy (Clemson).
Red and purple kales such as ‘Redbor’ and ‘Scarlet’ add colour.
Ornamental kale is edible but bitter; use it as a garnish (UF/IFAS).
Kale types compared
-
Curly (e.g. ‘Dwarf Green Curled’)
- Leaves
- Frilly green
- Height
- 45 to 60 cm (18 to 24 in)
- Best for
- Hardiness; small plots and pots
-
Tuscan (‘Cavolo Nero’)
- Leaves
- Long, puckered, blue-black
- Height
- 60 to 90 cm (2 to 3 ft)
- Best for
- Soups, stews and chips
-
Red Russian
- Leaves
- Flat, lobed, red-veined
- Height
- About 60 cm (2 ft)
- Best for
- Tender salad leaves, stir-fries
-
Red curly (‘Redbor’)
- Leaves
- Ruffled maroon
- Height
- Up to 1.5 m (5 ft) in a good year
- Best for
- Colour, salads
Heights from Clemson, UF/IFAS and the RHS. For winter picking in a cold garden, a curly kale; for cooking, Tuscan.
Where kale grows best
Kale is a cool-season crop and one of the hardiest leafy vegetables.
Sun. At least six hours a day (Clemson); the RHS finds it copes in light shade.
Temperature. It grows best below about 24 °C (75 °F) (Utah State). Young plants take -4 °C (25 °F); mature plants withstand -7 to -9 °C (15 to 20 °F) or colder (UMD, Clemson). If winter scorches the leaves, plants resprout in mild spells and in spring.
Frost sweetens it. Cold raises the sugar in the leaves, so autumn and winter crops often taste best (UMD, Penn State).
Warm climates. In Florida kale is a winter crop, sown from September to February (UF/IFAS).
- Sun
- At least six hours
- Mature plants survive
- -7 to -9 °C (15 to 20 °F)
- Best growth
- Below 24 °C (75 °F)
Soil
Kale prefers rich, well-drained, firm soil but grows in most soils (RHS).
Preparation. Weed, dig in plenty of well-rotted manure or compost, rake level and firm the soil well. Tall plants need firm ground to anchor them.
pH. 6.0 to 6.8 for cole crops (Penn State).
Rotation. Don’t grow kale where any brassica grew last year; three years is better (Penn State). If your soil has clubroot, grow kale in containers.
Planting
Sow in spring or summer, and plant out deep and firm at 10 to 15 cm (4 to 6 in).
Plant with the lowest leaves at the soil surface: tall plants need deep, firm roots.
When to sow kale
In the UK, sow outdoors from March to June, or indoors from March for an earlier start (RHS). Plants crop from September through winter.
In the US, plant transplants out four to five weeks before the last spring frost (Utah State). For an autumn crop, count back from your first autumn frost: days to maturity plus 10 to 14 days. UMD finds autumn the better season, because frost sweetens the leaves.
In warm-winter climates, sow from late summer through winter (UF/IFAS).
Baby leaves. Sow small batches every few weeks for salads over a long season.
- UK: sow March to June.
- US spring: plant out 4 to 5 weeks before the last frost.
- Autumn crops taste sweetest.
How to sow kale
Modules give sturdy plants that move without a check; direct sowing works too.
-
Sow in modules
Two seeds per module, about 1 cm (⅜ in) deep, and keep the stronger seedling (RHS).
-
Or sow outdoors
6 to 13 mm (¼ to ½ in) deep in a shallow drill (Utah State), in a seedbed or where the plants will grow.
-
Keep them bright and watered
Seedlings grow fast; transplants are ready in five or six weeks.
-
Thin
Direct-sown seedlings at three or four true leaves; replant the thinnings nearby (Utah State).
-
For baby leaves
Scatter seed thinly and cover with 1 cm (⅜ in) of compost; little or no thinning needed.
How to plant kale
Deep and firm, so tall plants stay anchored through winter.
-
Move them young
At 10 to 15 cm (4 to 6 in) tall, with four to six leaves (RHS, Utah State). Harden off indoor-raised plants first.
-
Plant deep
With the lowest leaves at the soil surface (RHS).
-
Space them
30 to 60 cm (12 to 24 in) apart by variety, in rows about 60 cm (2 ft) apart. Wide spacing gives light and air and deters disease. For baby leaves, about 7.5 cm (3 in).
-
Firm in and water
Press the soil firmly round each plant and water well.
-
Cover straight away
With fine insect mesh on hoops, and protect from slugs.
Care
Even moisture, mesh against pests, and stakes for tall plants in winter winds.
Cover the crop with fine mesh from planting: pigeons and caterpillars are the main threats.
Care by growth stage
Young plants
Protect: mesh and slugs
Water regularly, weed, and keep netted. See watering.
Summer
Water: 2.5 to 5 cm (1 to 2 in) a week
Water in dry spells; mulch to hold moisture. See watering.
Autumn
Harvest: lower leaves first
Start picking; stake tall plants. See protection and support.
Winter
Protect: from pigeons
Keep picking; frost sweetens the leaves. See harvesting.
Spring
Rotate: no brassicas next year
Pick the flower shoots, then clear and rotate.
Watering kale
Water seedlings and young plants regularly so the soil never dries out. After that, kale in the ground needs water only in long dry spells (RHS).
How much. In a dry climate, Utah State gives 2.5 to 5 cm (1 to 2 in) a week, watered deeply and less often.
Why it matters. Uneven moisture makes leaves tough and off-flavoured (Utah State).
Mulch with compost or manure to hold moisture and deter weeds.
In pots, water regularly, especially in summer.
Feeding kale
Kale usually needs no feeding on soil prepared with compost or manure (RHS). Cole crops are heavy feeders, so dig in plenty of organic matter before planting (Penn State).
On poor soil or in pots, give an organic-based, nitrogen-rich fertiliser to boost growth (RHS).
Before planting, Utah State works in organic matter and a complete fertiliser.
Protection and support
Kale needs no pruning, but it needs protecting.
Mesh. Keep plants under insect-proof mesh on hoops or canes to keep off pigeons, butterflies and other brassica pests (RHS). Gardeners’ World finds birds the biggest problem.
Support. Tall kale gets top-heavy. Planting deep and firm helps (RHS, Gardeners’ World).
Tidy up. Remove yellowing lower leaves.
Kale in containers
Kale grows well in pots, and a container avoids soil with clubroot.
Pot. At least 30 cm (12 in) wide and deep for a compact variety such as ‘Dwarf Green Curled’. Sow three seeds every 30 cm (12 in) and thin to the strongest (RHS).
Baby leaves. Sow thinly in any wide container of peat-free multi-purpose compost.
Care. A sunny spot, regular watering, and a nitrogen-rich feed now and then. Tuscan kale looks striking in a winter pot with pansies (Clemson).
Problems
Pigeons, caterpillars and aphids are the usual brassica troubles.
Common kale problems
Kale is less troubled than most brassicas; most damage comes from birds and insects.
Tough, bitter leaves
- Water stress
- Heat
Uneven watering or hot weather. Keep moisture even and grow for autumn and winter.
Plants rocking or falling over
- Wind
- Loose soil
Loose soil or shallow planting. Plant deep and firm, and stake tall plants.
Flowering in spring
- Biennial
Natural in the second spring. Pick the young flower shoots; the flowers also feed early bees (Gardeners’ World).
More problems with kale
Common pests
Caterpillars
Cabbage white butterflies and moths lay eggs; green caterpillars chew holes and hide in the plants. Mesh keeps them off; pick them off otherwise.
Mealy cabbage aphid
Common on brassicas. Tolerable on established plants, but it can make kale leaves inedible (RHS). Wash off with a strong jet of water.
Flea beetles
Pepper seedlings with tiny holes and can do severe damage (Penn State). Mesh protects young plants.
More problems with kale
Common diseases
Clubroot
Swollen, distorted roots and stunted plants. Rotate, or grow kale in containers of fresh compost.
Leaf spots and black rot
Alternaria and Cercospora leaf spots and black rot are the main diseases of greens (Clemson). Space plants widely for air flow (RHS).
Harvest & Use
Pick lower leaves a few at a time, from autumn to spring.
Harvesting kale
Kale is ready from about September in the UK (RHS), and 50 to 60 days after planting for quick varieties (Utah State).
Pick from the bottom up. Take two or three of the lower leaves from each plant at a time, once they reach full size, and let the young leaves at the top keep growing (RHS, Utah State). A plant crops for months this way.
After frost. Leave kale in the ground through winter and pick as needed: frost improves the flavour.
Baby leaves. Start at 10 to 15 cm (4 to 6 in) tall: pick individual leaves or cut the whole rosette, which will resprout (RHS).
Spring shoots. In the second spring, remove flower shoots to keep leaves coming (Gardeners’ World).
- Lower leaves first, a few at a time.
- Pick through winter.
- Frost improves the flavour.
Storing and using kale
Kale is best picked as you need it; plants store themselves in the garden all winter.
Fridge. Near 0 °C (32 °F) and high humidity, kale keeps two to three weeks (Utah State).
Freezing. Blanch the leaves, then freeze (Gardeners’ World).
Using it. Strip leaves from tough stems. Young leaves go in salads; older ones in soups, stews and stir-fries, or baked into chips.
More to Explore
Quick answers, guides that pair well with kale, and the sources behind this one.
Frequently asked questions
When should I plant kale?
In the UK, sow March to June; in the US, plant out 4 to 5 weeks before the last frost or for an autumn crop. See when to sow.
How do I harvest kale so it keeps growing?
Pick two or three lower leaves per plant at a time. See harvesting.
Does kale survive frost?
Yes: mature plants take -7 to -9 °C (15 to 20 °F), and frost sweetens the leaves.
Does kale come back every year?
Most varieties are biennial: they crop through winter, then flower the next spring and are done. A few heirlooms, such as ‘Taunton Deane’, crop for several years (RHS).
How far apart should kale be?
30 to 60 cm (12 to 24 in) for mature plants; about 7.5 cm (3 in) for baby leaves.
How do I stop pigeons and caterpillars eating my kale?
Grow it under fine mesh from planting. See pests.
Can I grow kale in a pot?
Yes, a compact variety in a pot at least 30 cm (12 in) wide and deep.
Is ornamental kale edible?
Yes, but it is usually bitter; use it as a garnish (UF/IFAS).
Related guides
Sources
- How to grow kale (opens in a new tab) Royal Horticultural Society
- Kale in the garden (opens in a new tab) Utah State University Extension
- Arugula, kale, mesclun, mustard and Swiss chard (opens in a new tab) Clemson Cooperative Extension
- Kale is a headless cabbage (opens in a new tab) Clemson Cooperative Extension
- Kale (opens in a new tab) UF/IFAS Gardening Solutions
- Growing leafy greens in a home garden (opens in a new tab) University of Maryland Extension
- Cole crops for the home vegetable garden (opens in a new tab) Penn State Extension
- How to grow kale (opens in a new tab) BBC Gardeners’ World