Leeks belong to the onion family. There are varieties for summer and winter cultivation. Leeks grown in the summer are thicker and not hardy. Leeks grown in the winter are hardy.

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Leeks (Allium ampeloprasum var. porrum). There are varieties for summer and winter cultivation. Leeks grown in the summer are thicker and not hardy. The thinner leeks grown in the winter are hardy. Pre-sow summer leeks in mid-January to mid-February in window sill seed trays. In April/May, the plants can be put in open ground. Early winter leeks – autumn leeks – sow in March in open ground in a seedbed; in June, when the leek plants are as thick as a pencil, transplant to the final spot. Young leek plants can also be purchased at garden centers.
Leeks like nutrient-rich, permeable soil; a little fertilization after the first month stimulates growth. Puddles of rainwater between leek plants increase the chances of rotting.
Leek are attacked by onion flies and leek moths, among others. Protect the leeks with insect netting. Unfortunately, onion fly larvae also emerge from the soil, especially if the soil is light and sandy.
In times of drought, give leeks some water daily. Not only in the soil, but especially in the leek stalk itself: the larvae of the leek moths in the heart of the stalk then drown.


Shiny spots on leaf, on the underside are insects: thrips (Thysanoptera).

Larvae of the leek or onion fly, photo: Rasbak – CC BY-SA 3.0

Leaf turns yellow and dies: leek or onion fly (Delia antiqua).

Damage by leek moth, photo: Rasbak – CC BY-SA 3.0

Tunnels and grated leaf surface: leek moth (Acrolepiopsis assectella).

Damage by the Allium leaf miner: photo: Henk Smits

Plants show tunnels in leek stalks and contain brown pupae: Allium leaf miner (Phytomyza gymnostoma).

Pierced roots, tunnels and rust-colored streaks on the root: carrot fly (Chamaepsila rosae).

Fungi & diseases

Leek rust, photo: Rasbak – CC BY-SA 3.0

Orange-brown spores on leek stems: leek rust (Puccinia porri).

Leek leaves start writhing and watery streaks with bacterial slime appear on the stems, leaf tips wither: Bacterial soft rot (Pseudomonas marginalis).

Infestation by white rot (Sclerotium cepivorum), photo: plantix.net

Leaves turn yellow and wilt; lower bulb and roots covered with thick, white mold. There are black spots on the affected parts: white rot (Sclerotium cepivorum).


Late spring – april – winter and autumn leek bolt. Harvesting before the end of March prevents flowering.

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