Planting Guide and Seed Saving Notes for Leeks

Leeks (Allium ampeloprasum)

The Roman emperor Nero listed leeks among his favorite foods and believed that they gave him a good singing voice. More recently, the leek has become a national symbol of Wales, with the Welsh enthusiastically integrating it into many of their dishes. A little less robust than an onion in flavor, leeks are used in stocks, soups, braised dishes, or caramenlized for a gourmet addition to pizza and quiche.

Nutrients: vitamins A, K, C, B6, and iron. 

How to grow Leeks from Seed

Bed Preparation

Leeks are cold hardy biennials that prefer rich, well-drained soil. Amend with compost prior to planting. Plant leeks in full sun.


Leeks can be grown from starts (young plants) or seed. Plant leek starts outdoors as soon as the soil can be worked in late winter-early spring. Space starts 4-6" apart in rows 12" apart. Blanching (preventing a portion of the plant from getting sunlight) is done to create the white, tender portion we most often eat. One planting method involves digging a 6" deep v-shaped trench and filling it with soil as the plants grow taller. The other less labor intensive technique is to poke 6" deep holes and insert leek starts. Soil can then be mounded around the base of plants as they grow. You can also place a portion of cardboard paper towel center around the lower part of the stem for blanching. Keep plants moist until well established and mulch to conserve moisture and minimize weeds.

Plant leek seeds indoors 6-8 weeks before the last frost date or in late summer for overwintering and early spring harvest. Sow seeds 1/4" deep and 1" apart. Seeds germinate best when soil temperatures are between 60-80°F. Seeds will sprout in 6-16 days. Thin seedlings so that mature plants are 4-6" apart. Hardened off seedlings can be transplanted outdoors as soon as the soil can be worked.


Leeks can be harvested on average in 95 days after planting or when plants are large enough to eat.

How to save Leek Seed

Leeks are biennial, meaning they flower, set seed and die during their second year of growth. Harvest seed when flowers begin to turn brown. Remove flower head and finish drying indoors. Store seeds in a cool, dry place. Seeds remain viable for 2-4 years.