Leeks grow best in the cool time of the year. Here are tips to grow leeks.
- Start leeks indoors up to 12 weeks before the last spring frost.
- Sow seeds indoors in a warm, well-lighted location—in a bright window or under grow lights.
- Sow seeds ⅛” (3 mm) deep in the seed starting mix.
- Firm seeds lightly and keep the soil mix just moist.
- Seedlings emerge in 8-16 days at 70°F (21°C).
- When seedlings are 2” (5 cm) tall transfer them to individual pots.
- Transplant leeks to the garden a week after the last frost or later when seedlings are 6-12” (15-30 cm) tall.
- Move seedlings to a sheltered place outdoors to “harden off” 1 week before transplanting.
- In the garden, space plants 2-4″ (5-10 cm) apart in trenches 5” (13 cm) deep–trenches spaced 6-10” (15-25 cm) apart. Or drop seedlings in holes dibbled about 6” (15 cm) deep leaving just one or two leaves above the soil surface.
- As leeks grow, fill in the trench gradually or, if planted on level soil, “hill” them by drawing soil up around the stems.
- Large transplants will grow the best leeks.
- Grow leeks in full sun to partial shade.
- Keep the soil moist during the growing season.
- Side-dress the plants with fish emulsion every two weeks.
- Leeks are ready for harvest 120-170 days after seeding, from early autumn to late spring.
- Short-season leeks (with thinner stems) can be harvested during the summer.
- Long-season leeks (with thick, cylindrical stems) are harvested from late summer through winter.
- Harvest when stems reach 1-2” (2.5-5 cm) in diameter and the leaves are 6-8” (15-20 cm) tall—after the trench has been fully filled in.
- Leeks do not store well; harvest as needed. In mild-winter regions, leeks can be left in the ground and lifted as needed.
Read more detailed leek growing articles at Leeks.