This odd brassica looks like a sputnik but don't let this put you off. It has a delicious smell and nutty flavour. More drought resistant than most brassicas, it succeeds where swedes and turnips fail. Green varieties are sown from mid-spring to mid-summer for summer crops; hardier purple varieties are sown from mid-summer for autumn and winter crops.
Jobs to do now
- Sow seeds in rows 30cm (12in) apart
- Thin out seedlings when they are 2.5cm (1in) high
- Keep the soil moist
Month by month
Create a firm seed bed in any reasonably light, fertile, free draining soil. Sow seeds, 1cm (½in) deep in rows 30cm (12in) apart from late February (under cloches or fleece) to early March, continuing until mid-August in warmer areas.
Sow a little and often, say every three weeks, for a constant supply.
In cooler areas and where soil is heavy clay, early crops can be sown in modules, hardened off and transplanted when the soil warms up, when they are a maximum of 5cm (2in) high.
Thin out seedlings when they are 2.5cm (1in) tall or the first true leaves appear, leaving a final spacing of 15cm (6in) apart.
Keep the soil constantly moist and weed free, watering before the onset of drought.
Net or fleece young plants, to protect against birds and cabbage root fly.
Cabbage root fly
White larvae approximately 5cm (2in) long, feed on the roots just below the soil surface, stunting growth and causing plants to wilt and die.
Grow under insect-proof mesh or horticultural fleece. Seedlings are most vulnerable.
Leaves are covered in small holes and damaged areas turn brown. Seedlings are particularly susceptible.
Grow plants under horticultural fleece and keep the soil moist. Water in nitrogen-rich fertilser to help the crop outgrow the pest.
Roots become swollen and distorted, and leaves become pale and yellow and wilt easily. Plants may die.
Improve drainage and add lime to make soil more alkaline. Do not grow in affected soil.
Harvest kohl rabi when young, between golf ball and tennis ball size. If you leave them too long they lose their flavour and tenderness.
With repeated sowings, plants can be harvested from May through to November, and the leaves can also be eaten.
Green varieties, sown from mid-spring, are ready in summer, while hardier purple varieties, sown in summer, provide autumn crops.
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