Serried ranks of blue-green leeks are the mainstay of the winter kitchen garden. Standing strong against frost and snow, the leafy plants provide food throughout the lean months of the year and, dug fresh from the garden, leeks have an earthy-sweet flavour that is intense and delicious - all the more welcome when other produce is thin on the ground.
Native to the Mediterranean area and parts of Asia, the leek (Allium porrum) was introduced to Britain by the Romans - and was known then as the por-leac - along with other members of the allium family including the onion (yul-leac) and garlic (gar-leac). It has been cultivated for millennia, although the modern, hybridised version is very different from the leek grown by the ancient Greeks and Romans, which was thinner and leafier, more like a spring onion. It is said that Emperor Nero ate large quantities of leeks to improve his singing voice, earning him the nickname 'Porophagus' or 'leek-eater', and perhaps this is why the Welsh, a nation of singers, have adopted the leek as their national symbol. The most enduring legend of its association with Wales is the story of the battle led by King Cadwallader of Gwynedd, who ordered his Welsh troops to wear leeks in their hats to distinguish them from the Saxons in a battle that took place in AD 640. The leek was a staple winter vegetable throughout the Middle Ages, mentioned in many written records of the time, but it remained unhybridised for hundreds of years, with improved cultivars becoming available in the nineteenth century only after a variety known as 'Gros-Court was discovered on a farm in Rouen.
Leeks are one of those crops that, once established, need little time lavished upon them. Only in the driest weather do they need watering, and most varieties are completely hardy, laughing in the face of the most extreme conditions, from gale force winds to ice and snow. Like most vegetables, early and late varieties are available to stretch the harvest season out, and early leeks can be started off in seed trays indoors to be planted out in late spring. The best results, however, come from outdoor-sown seeds that are later transplanted into their final positions. The transplanting is important as it allows the young leeks to be planted into deep holes, which will result in longer blanched stems - but it isn't essential. You can still achieve a crop of harvestable leeks just by sowing and thinning – they won't be as big as those that have been transplanted but, small and tender, they will still taste good.
Leeks can be sown outside as soon as the soil is warm enough in April, and should be scattered thinly along a drill about lcm deep.The seedlings are transplanted when they have reached about 20cm tall and the stems are the width of a pencil, usually in June. I love this task; kneeling on the edge of the bed, making holes with a dibber and systematically dropping each baby leek into its hole, then filling each hole with water to wash the soil around the roots before gently firming them in with your hands. The leeks should be spaced about 15cm apart in rows 30cm apart.
I always choose two varieties of leek to see me through the autumn and winter, one early or mid-season variety and one late. One of the best early leeks is 'King Richard', which can be ready to harvest as early as August. 'Jaune de Poitou' is another early, quick-growing leek with interesting yellowy leaves that look good in the kitchen garden in contrast to a bluer leek. Both 'King Richard' and 'Jaune de Poitou' are less winter-hardy than others, designed to be lifted early rather than be left for months in the cold ground. Mid-season varieties, for harvesting in November and December, include 'Monstrueux de Carentan', an old variety bred from the original 'Gros Court' leek in the nineteenth century, so-called because of its 'monstrous' proportions, and 'Oarsman', a modern F1 hybrid with dark green leaves.
My failsafe over-wintering variety is 'Bleu de Solaise', which has attractive blue-grey leaves that turn darker after a frost. The long, white stems are deliciously sweet and can be harvested all through the winter and into early spring. 'Musselburgh' is an old variety bred in Scotland, and still one of the most popular and reliable winter leeks, with sturdy fat stems and good flavour, while for looks I would choose 'St Victor' with its distinctive greeny-purple leaves that last through until spring.
Leeks are mainly trouble-free in terms of pests and disease. The only disease that can affect all alliums is rust, a fungal infection that is particularly prevalent if the soil is too high in nitrogen. Showing as bright orange rusty blotches on the leaves, it is disfiguring rather than fatal, and it can usually be avoided by choosing rust-resistant cultivars and making sure the soil isn't too nitrogen-rich (don't feed with a nitrogen fertiliser, for example). In the crop rotation, leeks are grouped with the other alliums-garlic, chives and onions, and the beds can be edged with marigolds or dotted with Verbena bonariensis for a more decorative tableau. It's even worth leaving a few leeks to go to seed in the spring for their tall stems, sometimes oddly kinked, with their pompom seed heads dancing about on top.