When to sow turnips

Turnips have two seasons, and the same plant is behind both. Early turnips, sold in Germany as Mairüben, go in from March to April and are pulled from May into June. They grow fast in cool, moist weather and are at their best small and tender.

Autumn turnips are sown from early July to mid-August, often straight after early potatoes, peas or broad beans have cleared a bed. They're ready from mid-September to November, and these are the ones that store. Teltower Rübchen, the small Brandenburg speciality, are sown a little later still, in the first half of August.

You can sow in between, but late-spring and midsummer sowings tend to struggle: heat and dry soil make roots woody and push plants into flower, and flea beetles are at their worst. March and April, then July and August, give the best crops.

For a steady supply of small roots, sow a short row every two to three weeks within each window rather than one long row at once.

Turnips are almost always sown straight into the bed. Pick an open spot with light, deep, humus-rich soil that doesn't stay wet. Acid ground suits them poorly and also favours clubroot, so lime it if a soil test says so.

Make drills 0.4–0.8 in deep and sow thinly. Rows 8–10 in apart suit early turnips; give autumn turnips 10–12 in. The seed comes up in about a week in mild weather and germinates in soil from about 41°F.

Thin in two steps as soon as the seedlings can be handled: early turnips to 4–6 in apart, autumn turnips to 6–8 in, large varieties to about 10 in. Crowded turnips make leaves, not roots. The thinnings are good in a salad.

In a 120 × 80 cm raised bed you fit four rows of early turnips, 32 to 48 roots depending on how close you thin. Autumn turnips need more room: three rows of six, about 18.

Even moisture is the main job. Turnips that dry out turn woody, hot and quick to bolt, so water in dry spells, especially summer sowings in July and August.

Turnips are light feeders. After a well-fed previous crop they need no fertiliser at all, and fresh manure or lots of nitrogen only gives leafy plants, a coarser flavour and more nitrate in the roots. Teltower Rübchen are the extreme case: their fine taste comes from poor, sandy soil.

Early sowings in March can bolt if a cold spell hits, because the chill already registers during germination. Choose a variety sold as a Mairübe or early turnip, and lay fleece over the row straight after sowing. The same cover keeps flea beetles off.

Keep the rows weeded while the plants are small; once the leaves meet, they shade most weeds out themselves.

Early turnips are ready about six to eight weeks after sowing. Pull them at golf-ball size for eating raw and no bigger than a tennis ball for cooking, roughly 2–3 in across. Left longer, they turn woody and pithy.

Autumn turnips take eight to ten weeks and are lifted from mid-September to November. They cope with light frost, but get them in before a hard freeze. Teltower Rübchen are picked small, about 2 in, from late September.

The leaves are a crop too. Young turnip tops cook like spinach, and in the Rhineland sowing turnips thickly just for their stems gives Rübstiel, a regional classic.

Early turnips are for eating fresh; keep them in the fridge and use them soon. For autumn turnips, twist off the leaves, bed the roots in boxes of slightly damp sand, and keep them cool and frost-free. Expect a few weeks, and up to a few months in a good cellar.

Early turnips (Mairüben) are quick, mild varieties bred to cope with spring sowing without bolting. They come white, white with a violet or red shoulder, or yellow, and are best eaten young and raw or lightly cooked. RHS award-winning examples include 'Tokyo Cross', 'Oasis' and 'Temari Red'.

Autumn turnips (Herbstrüben) are sown in summer, grow larger and keep in store. Any turnip sown in July or August is effectively an autumn turnip, but varieties sold for that season hold better in cold weather.

Teltower Rübchen are a small, tapered, white turnip from sandy soils around Teltow, south of Berlin, traditionally braised or glazed as a side dish. The name is protected for the regional product, but seed is sold to gardeners. Grow them hungry: in rich soil they lose the flavour they're prized for.

Flea beetles are the usual first problem: tiny jumping beetles that pepper seedling leaves with small round holes. They do most harm to young seedlings, above all in dry weather. Cover the row with fine insect mesh or fleece right after sowing, and keep the soil moist so seedlings grow past the vulnerable stage quickly.

Cabbage root fly maggots tunnel into the roots themselves, and because you eat the root, every generation of the fly can spoil turnips. The same mesh keeps the females from laying eggs at the base of the plants.

Clubroot causes swollen, distorted roots and stunted, wilting plants. Its spores stay in the soil for up to 20 years, so once a bed is infected, keep all brassicas out of it. Avoid acid soil, don't bring in brassica plants or soil from unknown sources, and rotate.

Turnips belong to the cabbage family, with cabbage, kale, kohlrabi, radish, swede and rocket. Leave three to four years before any of them grows in the same bed again, and count mustard green manure as a brassica too.

Mixed-planting tables pair turnips with lettuce, spinach, peas, beans, chard, tomatoes and dill. We found no trials showing a pest or yield benefit for any of these with turnips; treat them as tradition. Quick crops like lettuce and spinach do share a bed well for a practical reason: they are sown and cleared at similar times.

The one rule with a real reason: keep turnips away from beds that grew other brassicas in the last three to four years, because they share clubroot, flea beetles and cabbage root fly.