Leeks
Allium ampeloprasum. ALLIACEAE.
Planting, Growing, and Harvesting Leeks
You’ll find everything you need to know to plant and grow leeks in the accompanying table’s tabs:
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- How many leeks to plant
- Growing conditions for leeks
- When to plant leeks
- How to plant leeks
- Watering, fertilizing, and pruning leeks
- Companion plantings for leeks
- How to harvest, store, and use leeks
Growing Leeks
Leeks are cool-season, erect root vegetables with edible leaves, a milder-flavored relative to onions, also in the allium family. Leeks have stems of white turning green, 24–30 in. (60–75 cm) tall. They are topped with deep-green, fanlike foliage.
Leeks mature slowly and are prized for their mild, yet zesty flavor. With potato, chicken broth, and cream, a principal ingredient of vichyssoise, a cold soup and its warm companion, potato-leek soup.
Elephant Garlic (Allium ampeloprasum) is a distant relative of leeks and of the same family.
Leek Plant and Care Guide
How Much to Plant
Allow 12–15 plants per household member.
How to Plant
Seed germinates in 10–14 days. Note trench-planting and blanching instructions below and in the Care tab.
Average Climates: Sow seed indoors in flats at least 3 in. (75 mm) deep, filled with loose potting soil, 8–10 weeks before last expected frost, and harden seedlings 6–9 days before transplanting.
Mild-Winter Climates: Sow seed in full sun–partial shade in early autumn or late winter.
Autumn–Winter Gardens: Sow seed in early May for autumn harvest or in June for winter harvest. Plant transplants in June for autumn harvest or in August for winter harvest.
Sow seed in trenches 4–6 in. (10–15 cm) deep, 1/8-in. (3-mm) deep, 1 in. (25 mm) apart, thinning to 4–6 in. (10–15 cm) apart, in rows 18 in. (45 cm) apart. Set out seedlings in trenches 4–6 in. (10–15 cm) deep, 4–6 in. (10–15 cm) apart.
Plant successions every 2–3 weeks.
Best Conditions for Growth
Growing temperature: 45–85°F (7–29°C). Shade plants at temperatures over 90°F (32°C).
Soil Type and Fertility
Damp, well-drained, sandy loam. Fertility: Rich. 6.0–6.8 pH. Prepare soil at least 1 ft. (30 cm) deep.
Proper Care
Easy. Keep evenly damp; water when soil surface dries. Fertilize monthly with 5–10–10 formula; cultivate and water after fertilizing. Mulch. Blanch to ensure white root heads by gradually filling planting trench with sand as plants grow, mounding to base of first leaf junction. Pest and disease resistant.
Pairing Recommendations
Carrots, celery, garlic, and onions.
Maturity, Picking and Gathering
120–170 days. Best harvested as needed. Pull when stems are 1–2 in. (25–50 mm) wide and stalks are 16–24 in. (40–60 cm) tall. In cold-winter climates, in autumn pull roots and heel into moist wood chips.
How to Store and Preserve
Fresh, heeled in wood chips and placed in a dark, cool, moist spot, for 2 months [see Maturity/Harvest, above]. Good accompaniment to roasted potatoes, yams, and other mild-flavored tubers.