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A freshly pulled leek showing its long white shank and blue-green fan of leaves

How to Grow Leeks From Seed

By Maxim Kaufman — Founder & CEO, Organo Republic

Updated July 2026

Leeks are grown much like onions but instead of a bulb they build a long, tender white shank with a sweet, mild flavor far gentler than an onion. They need a long season and a simple hilling trick to blanch that prized white stem. Here is what makes leeks special and how to get the best from them.

This is the quick guide to Leek. For the full step-by-step on starting seeds, sowing, feeding, and troubleshooting onions, see our complete guide to growing onions from seed.

Quick start

Start seeds indoors 8 to 10 weeks before your last frost, then transplant seedlings into deep holes 6 inches apart in full sun and rich soil. As the plants grow, hill soil up around the stems every few weeks to blanch a long white shank. Keep them watered and fed, and harvest from about 120 days once the shanks are thick and tender.

Best tip

The secret to good leeks is blanching: hill soil up around the stems, or plant them in a deep hole and fill it in gradually, so the base grows long, white, and tender. Leeks are hardy and slow, so give them a long season, steady water, and rich soil, and you can even harvest them into cold weather.

At a glance

Botanical nameAllium ampeloprasum

Plant typeCool-season biennial grown as an annual

USDA zones3 to 9

SunFull sun (6 or more hours)

Days to maturity120 days

Height18 to 30 inches

Spacing6 inches apart

WaterSteady and even; about 1 inch a week

Uses

Leeks bring a gentle, silky sweetness to the kitchen. They are the heart of classic soups like potato-leek, and they braise, roast, and saute beautifully as a milder stand-in for onions. Use the tender white and pale-green shanks, saving the tough dark tops for stock.

Frequently asked questions

How long do leeks take to grow from seed?

Leeks are slow, needing about 120 days in the ground plus 8 to 10 weeks of indoor growing first, so plan on a long season.

How do I get a long white shank on leeks?

Blanch them by hilling soil up around the stems as they grow, or by planting them in a deep hole and filling it in gradually, which keeps the base pale and tender.

How is growing a leek different from an onion?

You grow leeks much like onions from seed, but they never form a bulb; instead you hill soil around the stem to build a long, mild white shank.

Can leeks survive frost?

Yes, leeks are hardy and their flavor even sweetens after a frost. In many regions you can leave them in the ground and harvest through late fall and winter.

Ready to grow your own? Our 8 Onion Variety Pack lets you grow Leek alongside seven other onions from a single order. For the full step-by-step, see our complete onion growing guide linked at the top of this page.

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Want more onions? These value packs pair leeks and onions with other varieties:

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By Maxim Kaufman — Founder & CEO, Organo Republic

Maxim founded Organo Republic in 2017 and personally selects, tests, and grows the heirloom, non-GMO varieties the company offers. Under his leadership, Organo Republic was named Agri Business Review’s Top Non-GMO Seed Variety Solution 2026.