Turnips grow best in cool, moisture-retentive soils and should be kept well watered before the onset of dry weather to stop them running to seed. Sow early varieties little and often for a constant harvest from spring until autumn. They mature in 6-10 weeks so may also be used as a catch crop or intercropped.
Sow seeds 1cm (½in) deep.
Early turnips: sow ‘Atlantic’ or ‘Milan Purple Top’ under cloches in February and other cultivars from March to June. Sow thinly with spacing between rows 23-30cm (9-12in) apart.
Maincrop turnips: sow thinly from July to mid-August. Space rows 30cm (12in) apart.
Turnip tops: sow thinly in August or September. Space rows 15cm (6in) apart.
Thin out turnips grown for their roots until they are eventually 15cm (6in) apart for early crops, or 23cm (9in) apart for maincrops.
Water during dry weather or the roots will be small and woody.
Troubleshooting Growing Problems
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.
Remedy: Grow under insect-proof mesh or horticultural fleece. Seedlings are most vulnerable.
Flea beetle: Leaves are covered in small holes and damaged areas turn brown. Seedlings are particularly susceptible.
Remedy: Grow plants under horticultural fleece and keep the soil moist. Water in nitrogen-rich fertilser to help the crop outgrow the pest.
Powdery Mildew: Appears as a white powdery deposit over the leaf surface and leaves become stunted and shrivel.
Remedy: Keep the soil moist and grow in cooler locations.
Club root: Roots become swollen and distorted, and leaves become pale and yellow and wilt easily. Plants may die.
Remedy: Improve drainage and add lime to make soil more alkaline. Do not grow in affected soil.
Early turnips: pull the turnips from May to September when the size of a golf ball for eating raw or the size of a tennis ball for cooking.
Maincrop turnips: lift the turnips from mid-October onwards when the size of a golf ball.
Turnip tops: harvest in March and April. Leave the plants to re-sprout as several cuts can be obtained.
Plant with: peas