How to grow Leek

Where to plant

Leeks grow in most soils as long as they are rich, moist, fertile and well drained. Work in compost or a complete fertilizer before planting, guided by a soil test. Give them full sun and a weed-free bed, as young leeks grow slowly and compete poorly for the first two months.

• Florida, the Gulf South, Texas, the Desert Southwest and Southern California: sow or transplant in fall for harvest through winter and spring. UF/IFAS suggests 'American Flag' for Florida.
• The Mid-South, Mid-Atlantic, Southern Plains, Pacific Northwest and Northern California: start in late winter or early spring, or sow in late summer where winters are mild enough to hold leeks in the ground.
• The Northeast, Midwest, Northern Plains, Mountain West and Alaska: start seed indoors 6 to 8 weeks before planting out in spring, or sow direct in early spring.

Choosing a variety

Utah State University Extension recommends 'Large American Flag', 'Comanche' and 'King Richard'.

How to plant

1. Sow seed 1/4 to 1/2 inch deep, either in the garden in early spring or indoors 6 to 8 weeks before transplanting.
2. Thin direct-sown seedlings to 4 to 6 inches apart in rows 8 to 16 inches apart.
3. To transplant, make holes about 6 inches deep with a dibble, drop a 10 to 12-inch seedling into each, and water it in without filling the hole. The hole fills gradually, which blanches the stem.
4. For direct-sown leeks, hill 2 to 3 inches of soil around the stems two or three times as they grow for a longer white stem.

Watering and feeding

Leeks have shallow roots and need regular watering all season; drought shrinks the stems and the yield. Soak the soil about 18 inches deep about once a week, and mulch to save water and smother weeds.

Side-dress with nitrogen once or twice during the season, for example in late spring and early summer in the North, to keep growth strong.

Pruning and care through the year

• Weed carefully, especially in the first two months, cultivating shallowly to avoid damaging roots.
• Rotate leeks away from where onions, garlic and other onion-family crops grew recently.

Harvesting

Lift leeks once the stems are at least 1 inch thick, which can be from about 60 days, though most take 100 to 120 days. Loosen the soil with a fork before pulling so the stems do not snap.

In most areas leeks can be left in the garden over winter: hill soil around them and cover with a thick mulch. In very cold areas, lift them and store in cold, humid conditions, such as in damp sand at 32 to 40°F. Leeks also freeze well after a 2 to 3-minute blanch.