key growing information

Growing Leeks From Seed

How to grow leeks from seed: fertile soil and pH, starting transplants, dibble planting, direct sowing, hilling for long white shanks, harvest and storage.

By Hensley’s Seed Co. September 3, 2026

Leeks - Key Growing Information

A row of leek plants in the field; harvest when white stems or shafts are approximately 3" (7 cm) long or greater.

SCIENTIFIC NAME:

Allium porrum

CULTURE:

Leeks are hungry plants and do best in rich soil with a pH of 6.2–6.8.

DAYS TO MATURITY:

Counted from transplanting; allow another 20–30 days when sowing direct.

TRANSPLANTING:

Sow in flats about 10–12 weeks ahead of the last frost, spacing seed ¼" apart and ¼" deep, or use plug flats and thin each cell to one seedling. From late spring, once plants are roughly pencil-thick and 8" tall, set them 6" apart in rows 12" or more apart, dropping each into a 6"-deep dibbled hole so only 2–3" of leaf shows. Leave the soil loose; rain or watering will fill the hole in.

DIRECT SEEDING:

In early spring, plant ¼–½" deep at 6 seeds per foot in rows 24" apart, thinning to 6".

AVG. DIRECT SEEDING RATE:

1,000 seeds sow about 165' and 1 oz. about 1,650'; for an acre at 6 seeds per foot in 30" rows, plan on 11 oz., or about 105,000 seeds.

BLANCHING:

Mound soil around the plants 2–3 times as they grow, a little higher each time. This pushes the leaves up and gives longer, blanched white stems with more to eat. Plants set with the dibble method need little or no hilling.

DISEASE:

HARVEST:

Once leeks are the size you want, loosen the soil with a spading fork and lift them.

STORAGE:

Trim and clean the leeks, then keep them boxed for several weeks in a humid cooler just above freezing, or in a root cellar with the roots set in moist soil, sand or peat.

TRANSPLANTS:

On average, 1 oz. yields about 6,000 transplants and 1 lb. about 96,000.

SEEDS/OZ.:

Between 7,700 and 10,700, averaging 9,400.

PACKET:

250 seeds per packet, enough for 38–40' or about 140 transplants unless noted.