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Leeks

Allium porrum

INTRODUCTION

A mainstay vegetable of the winter plot, Leeks are grown for the blanched part of the plant that is available from late August through till the following spring.

Incredibly winter hardy, leeks will hold well left in the ground for months and are suited to growing as baby Leeks or a highly suitable veg subject for the show bench.

A versatile vegetable in the kitchen, Leeks are nutritious and particularly high in iron and potassium.

Soil Preparation

Leeks are straightforward to grow but good soil preparation is recommended for the best results.

The growing site should be in a sunny position with organic material added well in advance of sowing and planting.

The ground should be light, fertile, free-draining and stone free. Heavy clay soils are not ideal.

Leeks need regular watering but do not appreciate wet soils.

Don't grow Leeks in soil that has had Alliums grown in the last two seasons. Always practice crop rotation.

Sowing & Planting

Leeks are best grown from seed raised plants rather than directly sown into their final position.

Seed can be sown in early spring into a seedbed or in containers undercover.

Prepare the seedbed by removing stones and weeds and rake to a fine tilth and gently firm soil.

Take out a drill (shallow trench) 2.5cm (1 inch) deep and sow seed thinly. Cover and water well.

If raising plants in pots, use at least a 3 litre pot filled with multi-purpose compost.

Sow seed thinly and cover with compost. This method works well if early sowings are made during February or March when outdoor soil temperatures are low.

There is no need to thin out seedlings. From June onwards, the Leek plants will be ready for planting.

Pull, or lightly fork, plants from the soil or pots, wash and trim roots to about 5cm (2 inches) from the base of the stem. Some foliage can be trimmed from the top of the plants as well. Neither of these drastic sounding procedures will harm the plants.

Prepare a shallow trench 10cm (4 inches) deep and using a dibber make holes into the trench 15cm (6 inches) deep. Drop a single plant into each hole but do not backfill the holes. They will fill themselves when watered.

Leave 20cm (8 inches) between plants and 30cm (12 inches) between individual rows.

Fill each hole with water immediately after planting. This will partially fill each hole with soil.

Growing & General Cultivation

Keep growing area weed-free but take care not to damage roots when hoeing.

Earth up around the developing stem to encourage more blanched stem and heavier yields.

Keep watering to a minimum as Leeks do not like to be overly wet but never let them dry out.

Feed once or twice during the growing period if required.

Pests & Diseases

Leeks are in general, a relatively trouble-free crop but the occasional issue may arise:

Leek Rust can be a problem during the summer, especially during wet weather. It appears as orange pustules on the foliage. Remove infected plants and avoid using the same ground for Leeks for several years. Rust-resistant varieties are available.

Bolting is the process where the Leek prematurely flowers and runs to seed. It is caused by fluctuating growing conditions and temperatures. Try to keep growing conditions as constant as possible.

Onion White Rot is a soil-borne fungal disease and a serious problem if you have it. It will affect all members of the Allium family and can persist in the soil for twenty years or more. Avoid growing any Onion related crops in the same soil.