TurnipBrassica rapa subsp. rapa

The turnip likes coolness: in spring, give it sun; for the summer sowing, choose a bed in partial shade or in the shade of a row of climbing beans, where the soil stays cool. It demands soil that does not dry out, preferably loamy, and dislikes chalk. It is a brassica, like cabbage and radish: do not sow it where either has grown in the last three years, because of clubroot and cabbage root fly. It gladly takes the place of peas or broad beans harvested in July, in soil enriched with nitrogen.

The turnip needs soil that is loose to twenty centimetres, moist and rich in humus, but without recent manure, which makes the roots hollow and spongy. Loosen with a broadfork, work in two kilos of mature compost per square metre, remove stones and rake the surface fine. In acidic soil, where clubroot thrives, a handful of ash or lime per square metre the previous autumn limits the risk. For a summer sowing after peas, simply cut the stems at the neck, scratch over the soil and rake: the legume roots have prepared the ground.

Two seasons here. The spring sowing, from late March to late April under fleece, gives tender turnips in May-June, but runs the risk of bolting if April is cold. The summer sowing, between 20 July and 25 August, is the most reliable in Belgium: it swells with the September rains, escapes the flea beetles and gives the sweetest autumn turnips. Avoid May and June, too hot and dry. Sow thinly in drills one centimetre deep and thirty apart, one seed every three centimetres, cover with fine soil and firm. Germination takes five to eight days.

The turnip is not transplanted; its taproot forks. To bring the spring harvest forward, sow in late February under a cold frame or tunnel in soil warmed by fleece laid ten days beforehand, with a fast variety such as De Milan rouge or Tokyo Cross, ready in six weeks. Ventilate as soon as the sun warms up and remove the protection in April. Sowing in module trays, planted out very young at two leaves without breaking the plug, remains possible for the impatient but gives less regular roots. For autumn turnips, there is no earliness to chase: the direct sowing in late July does it all.

The turnip does well in a container on a cool balcony, especially the round, fast varieties. Allow twenty centimetres of depth and a twenty-five-litre container for a dozen roots, filled with potting compost mixed with a third of soil, without fertiliser. Sow in April or August, in rows fifteen centimetres apart, thin to ten, and keep the compost moist at all times: water every day in summer. Move the container into afternoon shade during a heatwave. Harvest young, at ping-pong-ball size, and pick the young leaves, which are cooked like spinach; the insect-proof mesh is still useful even high up.

Sowing in May or June, in the height of the flea beetle season, and harvesting hot, hollow turnips. Letting the soil dry out for a week in August: the roots become fibrous and bitterness sets in. Not thinning, which gives clumps of leaves without roots. Adding fresh manure. Forgetting the insect-proof mesh and finding roots tunnelled by fly larvae at harvest. Letting the turnips grow beyond eight centimetres. Sowing turnips after cabbage or radish. Throwing away the tops, which make an excellent vegetable in soup or sautéed with garlic.

A tender turnip is a turnip that has never been thirsty. Water with a fine spray every two days until germination, then twice a week in spring, every two days in August in dry weather, giving five litres per square metre, in the evening. Regularity comes first: water stress followed by rain splits the root and makes it hot. Watering the foliage in hot, dry weather also unsettles the flea beetles. Once the September rains set in, let the sky do the work and step in only during a long dry spell.

The turnip needs no fertiliser in soil supplied with compost, and it makes full use of the nitrogen left by the peas or broad beans that preceded it. Excess nitrogen gives lush leaves and hollow roots. Mulch from thinning, with three to five centimetres of dried grass clippings or hemp mulch, to keep the coolness the turnip depends on, especially for the August sowing. This mulch also limits flea beetles, which like bare, warm soil. In October, thicken it to ten centimetres over the rows you will leave in the ground until the first frosts.

Thin as soon as the seedlings have three or four leaves, to ten centimetres for round varieties, fifteen for long ones or the large autumn turnips. Pinch out the surplus plants between two fingers so as not to disturb the neighbours, then water. The seedlings removed can be eaten as young leaves. Hoe shallowly between the rows after every heavy rain until mulching, without damaging the crowns. The turnip is not earthed up; if shoulders show above ground, simply draw a little soil over them. Cut yellowed leaves off at the base and remove without delay any plant that bolts.

Flea beetles riddle the leaves in spring and summer in dry weather; the cabbage root fly lays at the base and its larvae bore into the root. There is only one reliable defence: fine insect-proof mesh laid from sowing, edges buried, kept on until harvest, backed up by spray watering in the evening. Clubroot, which deforms the roots and makes the plants wilt, cannot be cured: a four-year rotation with all brassicas, drained soil and a little lime in acidic ground. Slugs are collected in the evening on young sowings. Turnip downy mildew remains rare if the rows are airy.

Late February: sowing under a cold frame or tunnel. Late March to late April: spring sowing under insect-proof mesh. April: thinning, hoeing, regular watering. May and June: harvest of spring turnips at ping-pong-ball size, tops in the kitchen. July: no sowing, preparation of the bed freed by the peas. From 20 July to 25 August: autumn sowing, mesh, watering every two days. September: thinning, mulching, rapid growth with the rains. October: harvest as needed, thickening of the mulch. November: lifting before the hard frosts and storing in sand in the cellar.

Harvest young: spring turnips at ping-pong-ball size, six weeks after sowing, autumn turnips at five to eight centimetres. Water beforehand, pull on the foliage while holding the soil, and pick the largest first to let the others swell. A forgotten root becomes fibrous, hollow and hot. The young leaves are harvested at the same time. To extend the season, stagger three summer sowings ten days apart until 25 August; autumn turnips withstand light frosts in the ground under a thick mulch and can be pulled until December in mild areas.