Onion family
Leek
Allium porrum
Timings for your region
Suggested: Moderate · Explained in the glossary
Start indoorsmid February – early April
Plantingmid May – early July
Harvestearly September – mid March
Practical tip
Drop the plants into a deep hole and just water them in rather than backfilling — that is what makes the white shank long. Winter varieties stand until March.
Origin & history
The leek descends from wild Allium ampeloprasum of the Mediterranean and was everyday food for Egyptians and Romans alike; the Romans carried it across the Alps, and Charlemagne’s estate ordinance of around 800 lists it as “porros” among the compulsory crops. Botanically it forms no bulb at all: the white shank consists of tightly rolled leaf sheaths layered like sheets of paper. In Wales the leek is still a national symbol, worn on the lapel on St David’s Day.
Varieties
Leeks come as summer, autumn and winter types, and when buying seed that is the only question that really matters. Summer varieties have pale green foliage and long, slender shanks and are ready from September, but they take no hard frost; winter types are recognisable by the dark blue-green of their leaves — they stay shorter and thicker, but stand in the bed into spring. Almost all common varieties are open-pollinated; if you would rather not raise plants for ten weeks yourself, buy bundled young plants in May or June.
Care
Leeks want steady moisture right through the season and a moderate feed in July, when the shank thickens — through longer dry spells they stay thin and stringy. Earthing up carefully two or three times lengthens the white part further, but never higher than just below the point where the leaves split: soil that slips between the leaf sheaths never comes out again and grits up the soup later. Keep the bed weed-free, because the narrow, upright leaves cast almost no shade and weeds have a clear run.
What can go wrong
Leek moth and leek miner fly are the two serious opponents: both eat tunnels and window-like patches into the heart of the plant, and only a fine-mesh crop-protection net keeps them out — left on from planting until November, because the second generation of the fly is not on the wing before October. Leek rust shows up as orange pustules on the leaves, usually in a damp late summer; generous spacing, restrained nitrogen and stripping off the affected outer leaves are entirely enough, and the harvest is not at risk from it. Do not bring leeks or other alliums back onto the same bed for three to four years.
Harvest, storage & kitchen
Leek is its own store: winter varieties come fresh out of the bed all winter long, and in a prolonged freeze a covering of leaves or fleece keeps the soil looser and the harvest possible. Lift them with a digging fork rather than pulling, or the shank tears off. In the kitchen slit the shank lengthways and rinse between the layers — that is where the grit sits; the dark green top is too tough to fry but the best thing you can put into a stock.
All timings are guide values for the given climate, not a guarantee. Weather, aspect and variety all have a say.