Growing Kale

Kale is a leafy cabbage without a head that forms strongly curled leaves on a tall stem. It is one of the oldest forms of cabbage and still looks much like wild cabbage. In northern Germany kale is the winter vegetable, and in the south too you harvest it fresh from the bed all winter long. There are low, compact varieties of 40 cm and old landraces such as Ostfriesische Palme that grow almost 2 m tall. Red varieties like Redbor or Roter Krauser also look really good in the bed. Kale is biennial: leave it standing over winter and it flowers yellow in spring.

Sow kale in May or June into a seed furrow or into pots, tall varieties from mid-April. After three to four weeks the young plants have three to four leaves and go to their final place from June until the end of July, after beans or peas even up to early August. Set the kale a little deeper than it stood in the pot, then it stands firmer later on. Low varieties need about 50 × 50 cm, tall ones 75 × 50 cm. Because it is planted so late, kale fits perfectly after early potatoes, peas, lettuce or garlic.

Kale likes a sunny spot, but it copes with a little shade as well. Deep, rather heavy loam soils with plenty of humus and enough lime are ideal. A pH around 7 or slightly above protects against clubroot. On sandy soils kale does fine too, as long as you add plenty of compost. It is less demanding than cauliflower and grows in a container from 10 litres upwards.

With kale you can choose between low, compact varieties such as Westerländer Winter or Niedriger Grüner Krauser, which hide under the snow and are especially hardy, and tall landraces such as Ostfriesische Palme or Lippische Palme. Red varieties like Redbor, Roter Krauser or Rote Palme are decorative and taste mild. Red Russian has flat, serrated leaves and works raw in winter salads too.

Kale is a hungry feeder. Work in ripe compost before planting; it does not take fresh manure, because that attracts the cabbage root fly. Keep the soil loose and weed-free until August, and young plants in particular need water in dry spells. Insect-proof netting put on right after planting keeps cabbage root fly, flea beetles and caterpillars away. Tie tall varieties to a stake before winter so snow and wind do not push them over. Kale takes frost down to about minus 8 °C, and more under snow or fleece.

Kale is tougher than most brassicas, but it is not spared completely. On soils with clubroot it fails just like other brassicas, even if some gardeners think it more resistant. So keep four years between it and other crucifers, and make sure there is enough lime in the soil.

The main pest on kale is the cabbage whitefly, a tiny white fly that sits in huge numbers on the undersides of the leaves in a warm late summer and autumn. Its sticky honeydew turns black with fungi. Netting from planting onwards and clearing away old cabbage stems help most, and you can also wash the flies off with a strong jet of water.

Caterpillars of the cabbage white, the diamondback moth and the cabbage moth eat holes in the leaves, the cabbage root fly lays its eggs at the root collar of young plants, and flea beetles riddle the leaves in summer. Here too, insect-proof netting gives reliable protection.

In cool, wet autumn weather white pustules sometimes appear on the undersides of the leaves, which is white blister. Red varieties are often attacked less by pests than green ones.