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Leek
Introduction
Leeks are in the Amaryllidaceae family, in the genus Allium, along with onions, scallions, and garlic. Their flavor is onion-like but much milder. Unlike onions, leeks don't form much of a bulb on the end of the stem. Instead, they remain cylindrical, with perhaps a slight bulge at the end. Historically many scientific names were used for leeks, which are now categorized as cultivars of Allium ampeloprasum.
Types and Varieties
| Type | Varieties |
|---|---|
| Summer/Fall |
Comanche King Richard (open-pollinated) Lincoln (open-pollinated) Surfer |
| Fall/Over-winter |
Lancelot Lexton Oslo Tadorna |
| Summer |
Biker Rally |
Soil Fertility
See the Onion, Scallion, and Shallot Soil Fertility section.
Planting
For best results, leek seeds should be sown in the greenhouse about 2.5 months before field setting. About 2-3 lb of seed are needed to raise enough plants to set an acre at average spacing (0.25-0.5 oz per 100 feet of row). Plant seeds no more than ½” deep in 288 deep cell trays. Before transplanting, 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 early July for a late fall harvest or, in milder locations, growers may wish to try overwintering the more cold tolerant leek varieties using straw mulch or row covers. Rows can be from 15-30" apart depending on equipment; plants should be about 3-6" apart (200-400 plants per 100 feet of row).
Field Culture
To develop a long, white stem, leeks can be planted in a trench 3-4" deep. The trenches are gradually filled as the leeks grow and then soil is hilled around stems to a height of 3-4". Several hillings may be required per season. Self-blanching varieties are grown without trenching and hilling and require less cleaning.
Harvest and Storage
Leeks can be harvested once the base reaches at least 1" diameter. Soil often clings to freshly harvested leeks. A pressure washer or hose nozzle with a strong jet of water can be carefully used to sufficiently clean soil particles from leeks for storage or market. Optimum storage conditions are 32°F with 95-100% relative humidity to prevent wilting. Leeks typically maintain quality in storage for 2-3 weeks. Under ideal conditions, up to 8 weeks is possible. Store separately from ethylene-producing crops.