Last Updated on February 18, 2024 by Jason Nguyen
With cultivar names like ‘Welsh Wonder’, ‘Colossal’ and ‘Unique’, leeks are staking their claim as large, robust and striking vegetables. The bit that’s eaten is the white part of the lower stem (above the root and below the tough green leaf tops). While rigid and usually called a stem or stalk, it isn’t a true stem but is made up of leaf bases tightly overlapping.
Although part of the onion family, leeks don’t form bulbs. Like onions, leeks are cool-season crops which grow best in the temperature range of 13°C–24°C.
Leeks are a must-have ingredient to make warming bowls of leek and potato soup and are an alternative to onions.
In cool and temperate areas, seed is sown from late summer to early autumn.
Seedlings are planted through autumn and winter. In tropical zones, leeks are a dry-season crop, sown in April.
Transplant seedlings into the vegetable garden when they are large enough to handle (around 12cm high).
Seedlings can be planted during autumn and early winter.
LEEKS ARE A MUST-HAVE INGREDIENT TO MAKE WARMING BOWLS OF LEEK AND POTATO SOUP AND ARE A USEFUL ALTERNATIVE TO ONIONS.
Leek Facts
Common name: Leek
Botanical name: Allium ampeloprasum Porrum Group (syn. A. pourrum)
Family: Alliaceae
Aspect and soil: Full sun; regular moisture
Climate: All
Habit: Annual bulb
Propagation: Seed, seedling
Difficulty: Easy
HOW TO GROW
To develop the tender white “stalks”, seedlings are planted into trenches or individual holes around 15–20cm deep.
Just cover the roots so the plants are stable. As the seedlings grow, earth up soil around the stem. This blanches the stem so it’s white or light green in color and tender. Watering will also wash soil in around the stem.
Leeks grow best in full sun with well-drained soil. With less light they’ll be spindly and may be prone to pests such as aphids. Well grown, they have few pest or disease problems but protect from snails and slugs with organic or homemade snail bait.
Water regularly (more frequently in hot weather) and liquid-feed every two weeks to encourage fast growth and plump leeks.
Water-stressed leeks can bolt to flower. Leeks are generally trouble-free but may be attacked by onion thrips, which cause white flecking on the leaves.
Diseases are kept in check by removing weeds and maintaining good spacing between plants.
HARVEST AND STORAGE
Where you have leeks in the garden, simply harvest the stems as needed.
Plants are ready to harvest when they are 2–2.5cm thick or around 12 weeks from transplanting seedlings.
After harvest, wash thoroughly then chop off the roots and tough leaf tops.
Next, wash the stalks clean of soil and they’re ready to chop. Washing carefully is important as leeks can be gritty if soil has worked its way between the leaf sheaths. To remove any dirt, remove the tough outer leaves and make vertical cuts in the stalk, then wash well.
Leeks are usually sliced finely and sautéed before being added to soups, stews or pies. This slow cooking softens them and helps develop the sweet flavor. The tougher leaf tops can be added to stocks for an oniony flavor. Leeks are rich in vitamins A and C.
