Lamb's lettuce (corn salad)Valerianella locusta

Lamb's lettuce grows almost anywhere, but it does best on a sunny bed, which catches the rare winter rays, with soil that is moist without being sodden. It follows on perfectly from early potatoes, onions, garlic or beans, pulled up between July and September, and slips in between rows of leeks or at the foot of cabbages, whose light shade it enjoys in August. Avoid soils that stay waterlogged in winter, where the rosettes rot, and do not resow it two years running in the same spot.

Unlike most vegetables, lamb's lettuce wants firm soil, not a fluffed-up bed. Do not dig: just scratch the surface to five centimetres to remove the debris of the previous crop and the weeds, rake finely, then firm with the back of the rake, a plank or a roller. No compost or fertiliser is needed; lamb's lettuce makes do with what the previous crop left and becomes prone to disease in soil that is too rich. If the soil is very dry in August, water the bed the day before sowing, never just afterwards, to avoid a crust.

In Belgium, the useful window runs from mid-July to the end of September. A sowing in late July or early August gives the largest rosettes from October; a sowing from late August to mid-September provides all winter, in smaller rosettes, and gets going again in spring; after 1 October, only a cold frame or tunnel allows a harvest, in March. Sow in rows fifteen to twenty centimetres apart, one seed per centimetre, or broadcast at two grams per square metre. Cover with five millimetres of fine soil, firm again and water with a spray.

Lamb's lettuce germinates between 10 and 20 °C and sulks above that: this is the real challenge of an August sowing. Sow in the evening, then cover the sowing with a plank, an upturned crate or shade netting, which you remove at the first shoots, after one to two weeks. Water every evening with a very fine spray to keep the surface moist without beating it down. Use seed under two years old, as its viability drops quickly. You can also pre-germinate the seed for three days in a damp cloth in a cool place before sowing: emergence is faster and more even.

If the bed is not free in August, sow in module trays or soil blocks, three or four seeds per cell, in a cool, shady place. Three weeks later, when the seedlings have four leaves, plant the whole plugs, without crumbling them, every ten centimetres each way, in firmed, watered soil. This method succeeds very well and lets you fill a bed the moment it becomes free, or slip clumps in between winter cabbages. Plants bought from a garden centre are set out the same way, until mid-October.

Lamb's lettuce is perfect in a window box or container twelve to fifteen centimetres deep, on a balcony, a windowsill or a terrace. Fill with firmed potting compost, broadcast the seed, cover with a few millimetres, firm by hand and water. Keep it cool and shaded until germination, then in the sun. The container can stay outside all winter; move it close to a wall in hard frost. Water little, only when the surface is dry. A one-metre window box provides a salad a week from November to March, cut rosette by rosette.

The first mistake is sowing in freshly dug, loose soil: the seeds sink too deep and germination is miserable. The second is sowing too early, in June, in the heat, or too late, in October, in the cold. Burying the seed two centimetres deep, watering with a jet or letting the surface dry out between showers ruins everything. Sowing too densely without thinning produces tiny rosettes and a hotbed of powdery mildew. Finally, giving up on a sowing that has shown nothing after a week is premature: lamb's lettuce takes its time, sometimes three weeks.

Until germination, keep the surface moist with fine waterings every evening. After that, water every three or four days in dry weather in August-September, five litres per square metre, in the morning by preference. From October, rain is enough and watering becomes harmful: too much moisture encourages powdery mildew, rust and rotting of the rosettes. Under a cold frame or tunnel, a light watering every two to three weeks in mild weather is enough all winter. Never wet the foliage in the evening, and ventilate the cover every frost-free day.

Lamb's lettuce needs no fertiliser or plant liquid: in soil that is too rich, it becomes drawn, yellows and catches every disease. The only essential care is regular, careful hand-weeding, as chickweed, speedwell and annual meadow grass come up at the same time as it does and smother it in a few weeks in our mild autumns. Go over the bed every ten days in September-October, then once a month. A very shallow hoeing between the rows is enough; the roots are close to the surface. Do not mulch, or only with one centimetre of hemp, to keep the rosettes clean without confining them.

When the seedlings have three or four leaves, thin to eight or ten centimetres by removing the weakest. Rosettes packed too tightly stay small, stretch and go mouldy from the inside. A broadcast sowing is thinned by shearing the densest patches with scissors. From November, remove yellow or slimy outer leaves as you go, along with whole plants that have rotted after snow. An overwintering fleece laid over hoops, rather than directly on the plants, keeps the leaves dry and clean, which matters more than the temperature.

Powdery mildew, a white felt on the leaves, and rust, brown pustules, appear in mild, damp autumns on sowings that are too dense. Sow thinly, thin, weed, do not water the foliage and remove affected rosettes; a spray of horsetail decoction in September limits the spread. Slugs nibble the young plants in August-September: trap planks lifted every morning, hunting with a head torch, ash or shells in dry weather. In winter, pigeons and rabbits go for the rosettes when everything else is scarce: fleece or a net keeps them at bay. Choose varieties resistant to powdery mildew such as Vit or Trophy.

In July, prepare and firm the bed freed by potatoes or onions. In August, sow twice a fortnight apart, shade, water every evening until germination. In September, thin, weed, sow one last time, set out slug defences. In October, weed again, stop watering, start harvesting the first sowing. In November-December, put up hoops and fleece, harvest when there is no frost. In January-February, clear snow off the fleece, remove rotten leaves, harvest. In March, harvest what is left before flowering, then hand the bed back to the spring sowings.

Cut whole rosettes with a knife just below the neck, as soon as they are six to eight centimetres across, starting with the largest to let the others grow on. Harvest in the late morning, when there is no frost, once the leaves have regained their suppleness, and only for the day's meal. A rosette from which you cut only the outer leaves regrows once. To extend into April, keep a late sowing under a cold frame, and let two or three plants flower in April-May: lamb's lettuce self-seeds, and you will find free seedlings to transplant in September.