Guide to Growing Leeks
Known for their onion-like punch, leeks are a delicious addition to savory, homemade dishes.
Although often thought of as a winter vegetable, leeks can be harvested from late summer to late spring and can be grown with little effort. They store well outside which, in turn, prolongs the harvest. Read on to discover how to make leeks work in your garden space.
How to Grow
Leeks need a sheltered, sunny site and fertile, well-drained, ideally slightly acid soil; preferably heavy and moisture-retentive. Turn over the bed the fall before planting, and incorporate plenty of well-rotted compost or manure. For an early start, sow seed under cover in late winter in trays or modules, to a depth of 1 inch (2.5 cm). When risk of frost has passed, harden off seedlings when pencil-thick, and transplant them into deep holes, 6 inches (15 cm) in depth, 6in (15cm) apart with 12in (30cm) between rows. Water around the stems, and allow the water to settle the soil around them rather than backfilling and firming by hand. Seed can also be sown directly outside in drills from early to mid-spring. For a continuous crop, sow at regular intervals, and transplant when seedlings are 8 inches (20 cm) tall. Once established, weed often, but water only in dry spells, and apply a high-nitrogen granular fertilizer in midsummer to late winter for early to late crops. As the leeks grow, pile earth around the stems to exclude light (“earthing up”); this blanches the stems, making them white and sweet-tasting—deep planting is a good start to this process. Harvest as needed, late summer to late spring.
To keep harvested leeks at their best, especially at the end of season when you need to clear the beds, bury the stems in shallow trenches. This keeps them fresh and frees up space for new-season crops.
Varieties of Leeks to Try
Leek rust can reduce your harvest, so it is important to choose resistant varieties, including ‘Apollo’ F1, ‘Autumn Mammoth’, ‘Oarsman’, ‘Swiss Giant‘ and ‘Toledo’. Other non-resistant varieties include: Bandit', 'King Richard’, ‘Lancelot’, 'Longbrow' and ‘Musselburgh’.
Watch Out for Pests and Diseases
Leek rust is most prevalent in wet seasons and causes orange patches on the outer leaves, which die back, reducing yield. There are no chemical controls, but it is important to remove plant debris and improve airflow.
Leaf-mining larvae of a fly and a moth may also attack leeks. There are no suitable pesticides, so grow leeks under insect-proof netting.