Growing leeks

Overview

Leeks are the backbone of the winter vegetable patch. They stand happily in frozen ground, ready to be dug for soups and pies on the bleakest days, and they follow neatly on from early crops such as potatoes or broad beans. The long white shank is what you are after, and it comes from planting deep rather than from any special skill.

Varieties to try

Pick varieties to spread the harvest. 'King Richard' is a slim, fast early leek for September and October. 'Musselburgh' is a reliable old Scottish variety that copes with cold, exposed gardens, while 'Bandit' and 'Northern Lights' have blue-green leaves and stand well into early spring. 'Carlton' is an F1 type that grows evenly and quickly from an early sowing.

Soil and site

Best soil: Deep, fertile, moisture-retentive soil enriched with well-rotted organic matter.

Give leeks a sunny bed that has had plenty of compost or manure dug in, ideally the previous autumn. They are hungry and thirsty and do best on deep, rich soil, though they are more tolerant of heavy ground than many crops. Keep them in your allium rotation with onions and garlic to avoid a build-up of soil-borne problems.

Sowing and planting

Sow thinly in a seed tray or modules under cover from February, or in a seedbed outdoors in March and April. When seedlings are roughly pencil thickness and 15–20 cm tall, usually in June or July, lift them and trim the roots and leaf tips slightly. Make holes 15 cm deep with a dibber, drop one seedling into each and fill the hole with water. Soil washes back in over the following weeks, blanching the stem naturally.

Spacing: Drop each seedling into a 15 cm dibber hole and fill it with water, not soil.

Care

Water well in dry summer weather, since leeks that go short of moisture stay thin. Hoe regularly while plants are small and give a nitrogen-rich feed in midsummer if growth looks pale. For longer white stems, draw soil up around the shanks in autumn or slip a cardboard collar over each plant, taking care not to let soil fall into the leaf joints.

Harvesting and storing

Lift leeks as soon as they are big enough to use, loosening the soil beside each one with a fork before easing it out; pulling usually snaps the stem. They store best left in the ground, so dig only what you need. If you need the bed in spring, lift the remaining plants and heel them into a shallow trench in a spare corner.

Common problems

Rust often turns leaves orange in late summer but usually fades as cold weather arrives. Wider spacing, good feeding and choosing resistant varieties help. Leek moth and allium leaf miner can tunnel into stems, especially in the south; covering plants with fine insect mesh from planting time is the most reliable defence. Trim off damaged outer layers in the kitchen.

Read more on the problems that most often hit leeks:

• Allium leaf miner
• Leek moth
• Onion fly
• Onion white rot
• Rust

Not sure what you're looking at? Try diagnosing it by symptom.

Month-by-month reminders

Jobs for leeks come round in January, February, March, April, June, July, September, October, November and December. Each month page lists the rest of the garden's jobs for the same weeks.

Grow alongside

• Onions
• Garlic
• Parsnips

Sources

Names follow Kew's Plants of the World Online; timings and spacings reflect UK growing practice and were checked against the references below. Text is our own. See our editorial policy.

• Kew Plants of the World Online — Allium ampeloprasum
• Wikipedia — Leek