🥬 Kale

Kale is among the hardiest and most productive winter crops, giving fresh leaves from autumn to spring when little else is available. It tolerates cold, partial shade and poor soil, and the flavour is even sweeter after frost.

It is a cut-and-come-again plant, so you can pick leaves for months from the same plant. There are curly, flat and ruffled types, with colours from deep blue-green to purple, making it attractive enough to grow in ornamental borders and pots.

Types and varieties

Kale is grouped by leaf shape, which also changes flavour and ornamental value.

Sow in April to July in modules, trays or a seedbed, 1–2 cm deep, and thin or prick out as they grow. Transplant when plants are about 10–15 cm tall, usually four to six weeks after sowing, spacing them 45–60 cm apart. In small gardens, sow thickly and pick the young seedlings as baby leaf.

Choose a position in full sun or light shade with fertile, well-drained, firm soil. Plant deeply and firm in, and water in well. Kale also grows well in large containers of at least 30 cm. Cover with netting from planting to protect from pigeons and butterflies.

Top tips

• Plant firmly into soil that has not been dug recently.
• Net straight away against pigeons.
• Sow thickly for baby kale leaves.
• Use pots at least 30 cm wide on a balcony.

Water well in dry weather and mulch to hold in moisture. Kale does not need much feeding, but a nitrogen-rich fertiliser a month after planting encourages leaf growth. Stake tall varieties in exposed sites, and earth up the stems in autumn to stop the wind rocking them.

Cabbage white caterpillars, whitefly and aphids can be a problem, along with pigeons, so net the plants and check regularly under the leaves. Clubroot may be a problem in acid soil; liming and rotation help. Remove yellowing leaves, which can harbour disease.

Top tips

• Check under leaves for butterfly eggs and squash them.
• Stake tall varieties in windy areas.
• Remove old yellow leaves to keep plants healthy.
• Lime acid soil and rotate crops.

Watch out for

Cabbage white caterpillarsAphidsWhiteflyPigeonsClubroot

Pick the lower leaves when they are 15–20 cm long, taking a few from each plant and leaving the crown at the top to keep producing. Pick young, tender leaves often and avoid stripping a plant, which weakens it. Remove any flower buds in spring to extend the harvest.

Harvest continues from autumn to March, with the flavour improving after frost. In spring, the plants send up flower shoots that can be picked like sprouting broccoli, and the yellow flowers are edible. Pull out the plants once the shoots go over.

Top tips

• Take a few leaves from each plant rather than stripping one.
• Pick after frost for the sweetest flavour.
• Harvest the spring flower shoots too.
• Remove flower buds to prolong leaf picking.

Strip the leaves from the tough stems and add to soups, stews and curries, sauté with garlic and chilli, bake into crispy kale crisps, or massage with oil and lemon for a raw salad. Cavolo nero is the classic choice for Italian ribollita, and young leaves can go into smoothies.

Kale keeps in a bag in the fridge for four to five days. It freezes very well: wash, strip from the stalks, blanch for two minutes, drain thoroughly and freeze in portions. Bunches can be stood in water in the fridge to stay fresh for longer.

Top tips

• Massage raw kale with oil and lemon to soften it.
• Bake at 150°C with oil for crisps.
• Blanch two minutes before freezing.
• Remove the tough central stalks before cooking.