LeekAllium porrum

The leek is undemanding about exposure: full sun suits it, but it tolerates light partial shade, which makes it a good candidate for the slightly less favoured beds. What it asks for is deep soil, moist in summer and free of standing water in winter, since it stays in place until March. Our loamy soils suit it very well; in clay, make sure of proper drainage. Preferably choose a bed that carried peas, broad beans or early potatoes, freed up in June, and avoid one that grew onions or garlic in the last three years.

The leek is greedy. The previous autumn, or at least a month before transplanting, spread four to five kilos of well-rotted compost per square metre, or composted manure, and work it in to twenty-five centimetres with a broadfork. Manure that is too fresh attracts the leaf miner and causes rot, so be patient if you have just spread some. Crumble the surface finely and remove stones and perennial roots. If your soil is very acid, which happens on some Ardennes loams, a light liming in autumn, one hundred grams of magnesian lime per square metre, helps growth.

Sow under a cold frame from February to March for summer leeks, and in an outdoor seedbed from mid-March to mid-May for autumn and winter leeks, the ones that really matter here. Choose a corner of fine soil, draw drills one centimetre deep and ten apart, and drop a seed roughly every centimetre; two grams of seed give nearly two hundred plants. Cover, firm, water with a fine spray and keep moist: germination takes two to three weeks at 12 °C. Sowing in a seed tray, then a seed box, works just as well on a cool windowsill.

A leek plant ready for transplanting measures fifteen to twenty centimetres and is the diameter of a pencil: that takes two to three months. Thin the seedbed to three centimetres as soon as the seedlings are up, hand-weed and water regularly, without excess. Nettle liquid diluted to 10 % in May stimulates growth. If the plants stay too thin, wait rather than transplanting puny specimens that would give spindly shanks. Conversely, a plant that is too large, left two months too long, bolts the same year. Module-grown plants bought from a garden centre in June are a good fallback.

Transplant from mid-May to late July, on an overcast day, after watering the seedbed. Lift the plants with a fork, trim the roots to two centimetres and the foliage by a third: this trimming limits evaporation and helps establishment. Some people leave the plants to dry for two days in the shade, which discourages the leaf miner. With a dibber, make holes fifteen to twenty centimetres deep every twelve to fifteen centimetres, in rows thirty-five centimetres apart. Drop one plant into each hole, without filling it in, and fill the hole with water: the soil closes over the roots by itself.

The leek accepts a container thirty centimetres deep, filled with rich potting compost mixed with a third of garden compost. Plant the young plants in holes twelve centimetres deep, every ten centimetres, and water generously. Place the container in sun or partial shade, never in a corner that stays sodden in the rain. A mulch of dried grass clippings or hemp keeps the compost cool. The shanks will stay shorter than in open ground, but perfectly tender. To blanch them, add compost as they grow or wrap each shank in a cardboard collar.

Transplanting plants as thin as matchsticks too early gives skinny leeks, whatever you do afterwards. Filling the planting holes in by hand stops the shank from lengthening: let the water do it. Planting close, at eight centimetres, does not give more harvest, only thin leeks and a well-established leek moth. Forgetting the insect-proof mesh in April and September means offering your leeks to the leaf miner, which rots them from the heart. Finally, sowing a single summer variety, which cannot take frost, deprives you of the best: winter leeks, harvested from November to March.

After transplanting, water every two or three days for two weeks if the weather is dry, then once a week in July-August, generously, fifteen litres per square metre, rather than little and often. The leek copes badly with summer drought, which hardens the shank and slows growth, but it also hates waterlogged soil. From September, rain is almost always enough. Water at the base in the morning, without wetting the foliage, so as not to encourage rust. A mulched soil halves the need for water.

A month after transplanting, once the plants have established, mulch between the rows with five to eight centimetres of dried grass clippings, straw or dead leaves: the soil stays cool, weeds are blocked, and the ground stays loose for earthing up. Feed in July and August with a watering of nettle or comfrey liquid diluted to 10 %, one watering can per square metre, two or three times in all. Stop all nitrogen from September: an over-fed leek stands up less well to frost and disease. The compost from the soil preparation does the rest.

The tender white of the leek is the part deprived of light. Three weeks after transplanting, hoe and draw a little soil against the shanks. Repeat every fortnight, in layers of three to five centimetres, never going above the base of the leaves, otherwise soil gets in between them and grits between the teeth. By autumn, the shanks are buried fifteen to twenty centimetres deep. The lazy get a comparable result by planting deep and slipping a collar of cardboard or drainage pipe around each plant. Remove yellowed leaves as you go.

The allium leaf miner flies in two generations, from mid-March to late April and from mid-September to mid-November. During these two periods, cover seedbed and bed with insect-proof mesh of under one millimetre, pressed well down to the ground. Pull up and bin misshapen shanks that carry small brown pupae. The leek moth bores into the heart of the leaves in July-August: cut affected foliage back to ten centimetres above the neck and it regrows healthy. Against late-summer rust, give plenty of air, avoid excess nitrogen, remove spotted leaves and spray horsetail.

In February-March, sow under cover, then in a seedbed, and lay mesh from emergence until the end of April. In May-June, thin, feed with nettle liquid, then transplant the pencil-thick plants. In July, water, mulch, start earthing up, watch for leek moth. In August, feed one last time, earth up, remove diseased leaves. In September, lay the mesh again against the second flight of the leaf miner, until mid-November. In October-November, harvest the autumn varieties and earth up the winter leeks one last time. From December to March, harvest as needed, and lift everything before flowering in April.

Harvest summer leeks from August, autumn leeks from September to November, and keep the winter varieties, such as Bleu de Solaise or Saint-Victor, for December to March. Lift each plant with a garden fork pushed in ten centimetres from the shank, and pull gently. In prolonged frost, cover part of the row with twenty centimetres of straw or leaves so you can carry on lifting. To free the bed in March, heel the last leeks in to a shady corner. Shanks that bolt in spring are not lost: their flower buds cook like asparagus.