How to grow leeks

Frost-hardy · Onion family

When to sow and plant

Start indoors 8–22 February
Sow outdoors around 22 March
Plant out around 19 April

Based on: average for Germany, last frost 19 April, safe from 6 May

Where the dates come from

The weeks come from our sources; the dates use the average frost in Germany. Enter a German postcode to get dates for your area.

Start indoors: 8–10 weeks before the last frost (Cornell Home Gardening: Growing Guide Leeks)
Plant out: from the last frost (Cornell Home Gardening: Growing Guide Leeks)
Sow outdoors: 4 weeks before the last frost (Cornell Home Gardening: Growing Guide Leeks)

Good and bad neighbours

Good neighbours · 2

Butterhead lettuceExpert rule· C
Leeks only grow strongly in late summer; until then quick lettuce fits in the row.
C: Expert rule with a reason
Butterhead lettuce
KohlrabiExpert rule· C
Leeks grow slowly; early kohlrabi is harvested before they need the space.
C: Expert rule with a reason
Kohlrabi

Disputed · 1

Chinese cabbage, KaleDisputed· X
BUND lists leeks as good cabbage neighbours; the Rhineland-Palatinate garden academy advises against them for Chinese cabbage and kale.
X: Sources disagree
Chinese cabbage Kale

Gardeners’ lore, not proven · 3

CarrotLore: good· D
Said to help against carrot and leek flies; no study on this exact pair.
D: Tradition, named by at least two sources
Carrot
Black salsifyLore: good· D
Traditional advice, not tested.
D: Tradition, named by at least two sources
Black salsify
CeleryLore: good· D
Traditional advice, not tested.
D: Tradition, named by at least two sources
Celery

Crop rotation

After the onion family, leave the bed free of it for at least 4 years.

The same species should go back to the same spot after a break of 3 years at the earliest.
Example: grown here in 2026, again from 2031.
Heavy feeders two years in a row on the same bed are not a mistake, but they take more out of the soil.

At a glance

Family: Onion family (Amaryllidaceae)
Nutrient needs: Heavy feeder
Frost: Hardy, tolerates frost
Spacing (row × plant): 30 × 15 cm (12 × 6 in)
Plants per m²: 22.2
Per square foot (30 × 30 cm): 4 plants
Life cycle: Annual
Harvest: After 100–120 days from sowing

Spacing according to Bayerische Gartenakademie (LWG): Sä- und Pflanztermine auf einen Blick (2018). Other sources: 51 × 10–15 cm (20 × 4–6 in) (Cornell Home Gardening: Growing Guide Leeks).

Questions and answers

When can I plant out leeks?

Plant out, average for Germany: around 19 April. Enter a German postcode above for your area, or your own frost date in the planting calendar.

How far apart should I plant leeks?

30 × 15 cm (12 × 6 in) (row × plant), according to Bayerische Gartenakademie (LWG): Sä- und Pflanztermine auf einen Blick (2018).

What grows well next to leeks?

Butterhead lettuce: Good neighbour (C), Kohlrabi: Good neighbour (C), Chinese cabbage, Kale: Disputed (X), Carrot: Gardeners’ lore, not proven (D) and Black salsify: Gardeners’ lore, not proven (D).

How long a break do leeks need in the same bed?

After the onion family, leave the bed free of it for at least 4 years. The same species should go back to the same spot after a break of 3 years at the earliest.

Sources

Show 11 sources

Retrieved on 23 October 2026. Facts in our own words, one source per value.