Leek

Allium ampeloprasum var. porrum

vegetable

verifiedReviewed by the GreenScout Team

Leeks are cool-season alliums with a mild onion flavor, prized for their long white shaft and tender green tops. They require a long growing season (120–150 days) and benefit from successive plantings for continuous harvest. Leeks are hardy and can tolerate frost, making them excellent for fall and early winter harvests.

Common Problems

Select the problem your Leek is experiencing to get a treatment guide.

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Slow Growthchevron_right

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Yellow Leaveschevron_right

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Brown Spotschevron_right

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Holes In Leaveschevron_right

Care Guide

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Light

Full sun, 6–8 hours daily for optimal growth and sweetness

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Water

Provide 1–1.5 inches per week; consistent moisture prevents splitting and improves shaft development

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Soil

Deep, well-draining, fertile loam with pH 6.0–7.0; incorporate compost; hilling up soil around stems bleaches the white shaft

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Fertiliser

Apply balanced fertilizer (10-10-10) monthly; side-dress with nitrogen-rich fertilizer mid-season to promote stem elongation

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Temperature

Prefers 60–70°F (16–21°C); tolerates frost and temperatures down to 20°F (−7°C); grows slowly in winter but improves flavor

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Humidity

Moderate humidity (50–70%); ensure good air circulation to prevent fungal issues

Toxicity

dangerousToxic to CatsdangerousToxic to Dogscheck_circleSafe for Children

Toxic to cats and dogs due to thiosulfate compounds that damage red blood cells; safe for children in typical culinary amounts

Common Diseases

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Common Pests

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Seasonal Care

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Resume regular watering and feeding as growth picks up.

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Peak growing season. Water and feed regularly.

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Reduce watering as growth slows. Stop heavy feeding.

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Minimal watering and feeding. Protect from frost if needed.

Frequently Asked Questions

Why do people mound soil around Leek stems?

Hilling up soil around the stems blanches the white shaft, keeping it pale and tender — this is a standard technique to maximize the prized white portion of the leek.

How long does it take to grow Leeks?

Leeks require a long growing season of 120–150 days — successive plantings help ensure a continuous harvest, and their frost tolerance makes them excellent for fall and early winter harvests.