🧅 Leek

Allium ampeloprasum
An onion that went to finishing school and learned to be subtle.
Sun
Full sun, 6–8 hrs
Days to harvest
120–150 days from seed — patience required
Spacing
6 inches apart in trenches or holes
Soil pH
6.0–6.8

How to grow

Start indoors 10–12 weeks before last frost — leeks are the slow food of the allium world. Sow 1/4 inch deep; trim seedlings to 3 inches tall a couple times to encourage stocky growth (it feels wrong, it's right). Transplant when pencil-thick into 6-inch-deep holes or trenches, dropping one seedling per hole and watering in — DON'T backfill; rain and watering settle soil around the shaft, blanching it white.

Hill soil up around stems through the season for longer white shanks — the white part is just stem that's never seen sun, which is also how vampires stay pale. In mild climates (zones 7+), leeks overwinter in the ground and you harvest as needed. In Florida, treat as a fall-planted, winter-harvested crop.

Water & feeding

Steady moisture — about 1 inch per week. Leeks have shallow roots and resent drying out. Feed at planting with worm castings in the trench and side-dress once mid-season; they're moderate feeders and respond well to the slow nitrogen release.

Common problems

  • Onion thrips: silvery streaks on leaves. Reflective mulch confuses them; spinosad or insecticidal soap for bad infestations.
  • Leek moth: row cover from transplanting is the best prevention — the caterpillars mine into the shaft where sprays can't reach.
  • Rust: orange pustules; improve airflow, avoid overhead watering, choose resistant varieties.

Harvest

Harvest anytime once shafts are 1+ inch thick — leeks don't have a 'ripe' moment, just a 'big enough' one. Loosen with a fork (they anchor like they pay rent) and twist out. Overwintered leeks get sweeter after frost; harvest before they bolt in spring.

Nerdy fact: Leeks are the national emblem of Wales, allegedly because Welsh soldiers wore them in their helmets to tell friend from foe in battle. Nothing says military identification like salad.

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