How to Grow Leek

Intermediate

Allium ampeloprasum

A hardy cool-season allium with a mild, sweet onion flavour. The edible white shaft is elongated by blanching — hilling soil around the stems as they grow. Tolerates frost and can overwinter in many climates.

Last updated: June 2026

Days to Maturity
90–150 days
typical
Per Square Foot
4
Plant Spacing
15 cm / 6"
Sun
6+ hours
Water
1.0" / 25 mm
Fertilization
moderate feeder

Growing Notes

Start indoors 10–12 weeks before last frost. Transplant into 15 cm deep holes and gradually fill as they grow to blanch the shaft. Harvest from pencil-thickness through winter. Very cold-hardy — flavour improves after frost.

Varieties & Cultivars

6 cultivars in our database. Click any card to see growing details.

Cold-hardy heirloom

(1)
American Flag
100–150 days Open-Pollinated

vigorous growth; mild sweet flavour; excellent for overwintering; also called Flag Leek

Height
18–24" (46–61 cm)
Yield / plant
—
Avg fruit
10.6 oz (300 g)
Support
none
Harvest
once
USDA Zones
3–10
Seed saving
moderate
Seed viability
3 years

Early-maturing

(1)
King Richard
75–90 days Open-Pollinated

mild flavour; does not need deep blanching; good for baby leeks

Height
12–18" (30–46 cm)
Yield / plant
—
Avg fruit
7.1 oz (200 g)
Support
none
Harvest
once
USDA Zones
3–9
Seed saving
moderate
Seed viability
3 years

Extra long white shaft up to 45cm

(1)
Mammoth Blanche
120–150 days Open-Pollinated

mild flavour; needs long growing season; impressive kitchen leek

Height
18–24" (46–61 cm)
Yield / plant
—
Avg fruit
14.1 oz (400 g)
Support
none
Harvest
once
USDA Zones
3–10
Seed saving
moderate
Seed viability
3 years

French heirloom

(1)
Blue Solaise
100–150 days Open-Pollinated

extremely winter-hardy; deepens in colour after frost; excellent keeper

Height
14–22" (35–56 cm)
Yield / plant
—
Avg fruit
8.8 oz (250 g)
Support
none
Harvest
once
USDA Zones
3–10
Seed saving
moderate
Seed viability
3 years

French variety

(1)
Carentan
75–85 days Open-Pollinated

mild flavour; compact plants; good for baby leek harvest; reliable performer

Height
12–18" (30–46 cm)
Yield / plant
—
Avg fruit
7.1 oz (200 g)
Support
none
Harvest
once
USDA Zones
3–9
Seed saving
moderate
Seed viability
3 years

Scottish heirloom since 1834

(1)
Musselburgh
90–120 days Open-Pollinated

extremely cold-hardy; mild sweet flavour; reliable overwintering variety

Height
16–24" (40–61 cm)
Yield / plant
—
Avg fruit
10.6 oz (300 g)
Support
none
Harvest
once
USDA Zones
3–10
Seed saving
moderate
Seed viability
3 years

Companion Planting

What to grow alongside leek, and what to keep apart.

Plant With

Lettuce : Lettuce fills space between leek rows in early season
Celery : Celery and leeks share similar growing conditions and deter each other's pests
Onion : Fellow alliums share pest-deterrent properties and growing conditions
Strawberry : Leek scent deters strawberry pests; complementary root depths
Parsley : Parsley attracts beneficial insects that help protect leeks
Spinach : Spinach provides early ground cover between slow-growing leeks
Carrot : Leeks repel carrot fly; carrots repel leek moth — classic companion pair
Beet : Beets and leeks complement each other in root depth and growing speed

Keep Apart

Peas : Peas and alliums are antagonistic; leek root exudates inhibit pea growth
Beans : Beans and leeks inhibit each other's growth — alliums and legumes are antagonistic

Square Foot Spacing

4 per sq ft

6" apart (2×2 grid)

View full spacing chart →

Ready to grow leek?

Plan your garden with exact spacing and zone-specific planting dates. An AI companion helps with the rest.

Start Planning Free →