For best results, leek seeds should be sown in the greenhouse about two and a half months before field setting. About 2 to 3 pounds of seed are needed to raise enough plants to set an acre at average spacing (1/4 to 1/2 oz per 100 feet of row). Before setting, clip plants to a height of 3” to reduce wind damage in the field. Set plants in the field from late April to late May depending on location and earliness desired. Plants can be set in late July for a late fall harvest, or in milder locations, growers may wish to try overwintering leeks using a straw mulch. Rows can be from 15” to 30” apart depending on equipment; plants should be about 3” to 6” apart (200 to 400 plants per 100 feet of row)
To develop a long, white stem, leeks can be planted in a trench 3” to 4” deep. The trenches are gradually filled as the leeks grow and then soil is hilled around stems to a height of 3” to 4”. Soil particles have to be cleaned from the leeks when preparing for market. Self-blanching varieties are grown without trenching and hilling and require less cleaning.
For Current information on production methods (including varieties, spacing, seeding, and fertility), weed, disease, and insect management, please visit the New England Vegetable Management Guide website