When do I sow leek seed?

March to April indoors or in a seedbed. Transplant to their final position in June or July when seedlings are pencil-thick. Earlier sowings (February under glass) can be lifted as early as September; later sowings (May) crop from December through to April.

Why do you drop leeks into holes without filling them?

The 15 cm-deep air pocket around the lower stem is what blanches it white. If you fill the hole with soil, you get a thinner, less-blanched leek with grit working into the leaf joints. Leave the hole open after planting; just water it in. Soil naturally falls in over the next few weeks as the plant grows.

What's allium leaf miner and how do I stop it?

Phytomyza gymnostoma — a small fly whose larvae tunnel into leek (and onion, garlic, chive) stems, leaving them slimy and unusable. First recorded in the UK in 2002 and now widespread. The only reliable defence is netting with 5 mm enviromesh from March until lifting. Two generations a year — adults active March–May and September–November.

What variety of leek is best for the UK?

Musselburgh has been the UK standard since the 1830s — reliable, hardy, fat shanks, good flavour. Modern alternatives: Toledo and Bandit (overwintering F1s with excellent cold tolerance), Oarsman (early season), Apollo (mid-season). For overwintering through the worst weather, choose an F1 bred specifically for it.

Can I grow leeks in containers?

Possible but limited. A deep (40 cm+) container holds 4–6 leeks if you really want them. Yield is modest and you lose the blanching depth the dibber method gives in the ground. Use the bed space if you have it.

When are leeks ready to harvest?

October onwards, when shanks are at least 2 cm thick. They keep cropping right through winter and into April. Lift as needed — they store far better in the ground than out of it. By May they bolt and become woody; lift any remaining before then.

Lauch

Allium ampeloprasum var. porrum

Sow leek seed from March to April indoors or in a seedbed; transplant 15 cm apart into deep dibbed holes in June or July. Leeks are very hardy (RHS H6) and crop from October right through to April, sitting in the ground through the worst of a UK winter without protection. Drop the seedlings into 15 cm-deep holes made with a thick dibber and water in but don't fill the holes with soil — the gap blanches the lower stem white. Choose Musselburgh (the heritage UK standard), Toledo or Bandit (overwintering F1s). Watch for allium leaf miner from spring — netting from March stops it; otherwise the maggots tunnel into the shanks.

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