How to grow Leek

Allium ampeloprasum

A hardy, cool-season vegetable grown for its long white stems. It is usually raised from seed in modules and planted out when pencil-thick; winter varieties can stay in the ground through hard frosts.

Quick facts

Type	Vegetable
Family	Amaryllidaceae
Light	Full sun
Soil pH	6–7
Frost	tolerates light frost
Soil for sowing	from 7 °C
Germination	10 days
Seedlings ready	60 days
Sowing to harvest	170 days
Where it grows	Greenhouse, Open ground, At home

When to plant

Sow for seedlings about 10 weeks before planting out.

It tolerates light frost: plant out in open ground about three weeks before your last spring frost.

In an unheated greenhouse everything moves about three weeks earlier.

The first harvest comes about 170 days after the shoots appear.

Frost dates · When to plant

Care

Greenhouse

Stage	Watering	Temperature	Feeding
Germination	every 2 days	18…29 °C	—
Seedlings	every 3 days	15…21 °C	—
Growth	every 4 days	15…21 °C	nitrogen, 21 days into the stage; nitrogen, 63 days into the stage
Harvest	every 7 days	—	—

Open ground

Stage	Watering	Temperature	Feeding
Germination	every 3 days	18…29 °C	—
Seedlings	every 4 days	15…21 °C	—
Growth	every 7 days	15…21 °C	nitrogen, 21 days into the stage; nitrogen, 63 days into the stage
Harvest	every 7 days	—	—

At home

Stage	Watering	Temperature	Feeding
Germination	every 2 days	18…29 °C	—
Seedlings	every 3 days	15…21 °C	—
Growth	every 4 days	15…21 °C	nitrogen, 21 days into the stage; nitrogen, 63 days into the stage
Harvest	every 5 days	—	—

Growing notes

Light

Needs full sun, at least 6 hours of direct light a day; 8–10 hours is better.

Soil

Fertile, free-draining soil with plenty of garden compost or well-rotted manure, pH 6–7.

Care

Plant seedlings about 20 cm tall, roughly eight weeks old, in holes 15 cm deep and 15–20 cm apart. In dry weather soak the soil deeply about once a week. Side-dress with nitrogen twice in summer, about six weeks apart. Earth up the stems two or three times to blanch them, keeping soil out of the leaves. Lift leeks from late summer once the stems are about 2.5 cm thick, usually 3–4 months after planting out.

Pests and diseases of Leek

Sources

Figures checked against these sources.