Leeks (Allium porrum) are very hardy members of the allium family. Harvested late in the year, they can be left in ground until required, cropping from early autumn into late spring.
Soil Type: Deeply worked, non-acid, soil that is rich in organic matter.
Conditions: Full sun
Ease of Cultivation: Easy
Type: Stem Vegetable
Hardiness: Hardy in the UK.
When to Sow: March to April
Harvest Season: October to May
Leeks like a soil rich in humus and nutrients but are less demanding than others from the onion family. The soil should be deeply dug before planting and not compacted.
Incorporate a general fertilizer into the surface about a week before planting.
Sow the seeds thinly in a nursery bed or in individual pots, deep modules or root trainers, from March to April. Once direct sown seedlings reach 2 inch (5cm) high, prick out to 2 inch (5cm) apart.
For an early crop, sow in trays or modules in early February with a little bottom heat. Around mid April, transfer to a cold frame to harden-off.
Transplant to the growing site when the seedlings are about 8in (20cm) tall, usually in June and July. Any spare seedlings can be used in the place of spring onions in stir fries.
Plant in rows 2ft (60cm) apart with about 6 inch (15cm) spacing between plants, depending on variety.
Plant using a thin dibber. Make holes 6 inch (15cm) deep and simply drop the seedling in. Water well to settle them in.
Leeks need very little attention apart from weeding and ensuring the crop is watered in dry weather. Gradually earth them up as they grow to help blanch the stems white (by excluding the light). Take care not to earth up too high or soil will get between the leaves, which is difficult to wash out during preparation.
Ensure the soil does not become waterlogged as this can cause rotting.
Can be affected by Leek moth and other allium pests.
Apart from rust, leeks are mainly disease-free. Rust resistant varieties are available.
Lift your first leeks soon as they reach a reasonable size, usually about 40 weeks after sowing. Hardy varieties can remain in the ground throughout the winter, to be harvested as and when needed. Fast growing varieties like 'Nipper' can also be harvested early as baby leeks, when they are about the size of spring onion.
Mature leeks are at there best when the stems (shanks) are about 3/4 inch (2cm) thick. Harvest by loosening the soil first with a fork and gently easing them out of the ground, roots and all.
Slice off the roots and cut away the top part of the leaves, leaving a little of the green. Peel off the coarse outer leaves and wash thoroughly, ensuring that no grit remains lodged between the leaves.
Smaller leeks can be left whole. Larger leeks can be split lengthways, or sliced into thick rings.
Boil for 8 to 10 minutes and drain thoroughly. Alternatively, add to a casserole, soup or stew recipe.
Leeks can be used as a substitute for onions in some recipes such as stews.
Some varieties mature quickly and others are able to stand longer through the winter.
Leek 'Apollo' is a high yielding maincrop variety with short uniform shafts and pale leaves. Good rust resistance. Ideal for close planting.
Leek 'Autumn Giant 2 - Argenta' is good quality, thick, long leek of excellent mild flavour and high yield. Can be sown early or late. Harvest from October to May. Available at Thompson & Morgan.
Leek 'Autumn Giant 2 - Porvite' produces mid green, erect foliage, and heavy, uniform stems. Good resistance to bulbing and bolting, as well as high rust tolerance. Available at Thompson & Morgan.
Leek Autumn Mammoth Tornado is a vigorous, thick stem, variety with good disease resistance. Good for the show bench. Available at Marshalls.
Leek 'Below-Zero' (F1 Hybrid) has dark leaves and pure white straight stems with long standing ability, plus good bolt and rust tolerant. Harvest from Christmas to May. Available at Thompson & Morgan.
Leek 'Blauwgroene Winter - Bandit' produces dark leaves and thick, pure white stems. Excellent winter hardiness and good tolerance against rust and bolting. Harvest from winter through to spring. Height: 18 inches (45 cm), spread 8 inches (20 cm). Available at Thompson & Morgan.
Leek 'Bleu de Solaise' a French heritage leek. Reliable, very hardy, maincrop variety with deep purplish-blue leaves and short, heavy stems. Stands well. Harvest from Christmas to April. Available at Thompson & Morgan.
Leek 'Bulgaarse Reuzen - Lincoln' is a popular early cropping variety. An early spring sowing will provide medium sized white stems for picking in late summer, or leave to mature for harvest right through autumn. Good bolt and disease resistance. Available at Thompson & Morgan.
Leek 'King Richard' another high yielding all round favourite, that can be grown as a mid season leek or baby leek. It has a long white body and pale green leaves, with a mild sweet taste.
Leek Krypton is a compact leek with an upright habit. Ideal if space is limited. Good as a baby leek.
Leek 'Mercurian' is a vigorous autumn variety with long white stems. The upright, non-drooping leaf habit allows for good air circulation, minimising the risk of mould or infection. Available at Thompson & Morgan.
Leek 'Murcia' is a very hardy and resilient variety, that stands well. Harvest from October to January. Available at Thompson & Morgan.
Leek 'Musselburgh' is a popular mid season variety with good heritage, named after a Scottish town. Hardy and reliable, it produces short sturdy stems with good flavour. Harvested from September to the new year. Available at Van Meuwen. Available at Thompson & Morgan.
Leek 'Neptune' produces tasty, thick stems that are are ideal for slicing and adding to stews, soups and sauces. Height: 45cm (18). Spread: 30cm (12). Available at Van Meuwen. Available at Marshalls.
Leek 'Nipper' a fast growing 'baby leek' variety that can be ready to pick in just 10 weeks. Harvest at 'spring onion size'. The flavour is milder than spring onions. Delicious in stir fries and salads. Available at Thompson & Morgan.
Leek 'Northern Lights' (F1 Hybrid) a tasty maincrop leek, with attractive blue-green leaves. Popular for both the show bench and the kitchen. Excellent winter hardiness. Available at Thompson & Morgan.
Leek 'Oarsman' (F1 Hybrid) has dark, erect foliage and uniform pure white, long stems. Bulks up quickly. Good rust and bolting tolerance. Available at Thompson & Morgan. Available at Marshalls.
Leek 'Porbella' a good maincrop leek for harvesting between October and February. Pure white, thick stems and dark green leaves. Good rust resistance. Available at Thompson & Morgan.
Leek 'Toledo' is a high yielding variety, producing smooth uniform medium length shanks from early winter to mid spring.
Leek Tornado is a high yielding, long shanked leek. Excellent cold weather tolerance. Can also be sown early for an earlier crop. Available at Gardening Direct.
Leek Zermatt is a popular early maturing form, ideal as a baby leek. The long shank and erect leaves can also be left to mature. Good rust resistance.