Leeks

Leeks provide good value for money as a crop from the garden and their versatility in the kitchen is on a par with their relatives, the onion.

St. David, the patron saint of Wales, ordered his soldiers to attach a leek to their caps prior to their battles with the Saxon invaders. Indeed, the Welsh who made the leek one of their national symbols also had other views on this great vegetable. According to lore, if a girl slept but kept a leek under her pillow on St. Davids Day then she would see her husband-to-be in her dreams. 

In earlier times, the Emperor Nero considered the leek to be the reason for his wonderful singing voice. So when Rome burned, he who had fiddled might well have just dined on one of his favoured dishes, a leek soup.

The leek (Allium porrum) must be one of the easiest vegetables to grow with relatively straightforward maintenance. It is a hardy biannual which is cultivated annually for use in autumn and winter. It is picked when other vegetables are not available in the garden. The thick, white, stem-like portion is made up of tightly concentric, succulent layers of leaf bases where each then parts at the top to form large, grooved strap-shaped, grey-green leaves. The stems have a mild, slightly onion flavour and are usually blanched before harvesting.

Successional growing means leeks can be available all year round. They are also known for their tremendous culinary versatility because the vegetable is a base for other vegetable and meat dishes. They offer a highly distinctive flavour to basic stocks,  soups, stews, sauces, savoury tarts, pasta, roasts and risottos. Also delicious when sliced, boiled and covered in cheese sauce for a tasty addition to a roast dinner. Our favourite recipes include chicken and leek pie, and of course leek and potato soup.

Cultivation

Leeks thrive in any ordinary garden soil which is well-drained. They are best grown on ground that has had early peas, potatoes and salad crops following their harvest. They will be in the ground for some time so it is one of those crops where you would not expect to grow something else relatively soon. The ground should be dug deeply and a bucket of well-rotted manure or compost added per sq. yard. I apply a dressing of fish manure at about 3 oz. per sq.

Sowing Guide

Leeks are generally grown outdoors. The seed is usually sown indoors from January to February in individual modules or seed trays. If sown outside, then in late March-April in a prepared seed bed.

Indoor sowing is best in multi-purpose compost or one that is at least free-draining where the seeds are sown thinly. They are covered with a 1cm (1/2”in) layer of sieved compost and then watered in gently. A temperature of 10-15°C (50-59°F) should be enough but once the seedlings appear, they can be kept cooler but must be frost free.

Planting Out

Let the seedlings get to a pencil thickness which is about 20cm (8”) tall. If sown indoors, plant out but acclimatise them by placing the tray or module outside in the day and putting back inside again at night. I usually give between seven and ten days. Plant out is sun or semi-shade.

Space the young plants about 15 to 23cm (6-9in) apart and 30cm (9-12in) between rows. The growing distances depend on the type of cultivar grown.

The soil needs to be raked and well watered with plenty of compost or other organic matter added. Best with well-draining soil.

Make a hole using a dibber or thick stick to a depth of 15cm (6”). Gently place a leek in each hole and then water in. backfilling is not needed with watering as the soil should be loose enough. The lower part of the stem should blanch or turn white in the process of growing.

Aftercare

Maintenance really isn’t necessary once they are sown save for weeding and watering during dry periods. Cover the young plants to prevent birds like pigeons and blackbirds from tugging and pulling out the seedlings. It’s the same with onions and garlic especially in the winter and spring months. From Autumn onwards, start ‘trenching’ by drawing soil up around them as the stems will need to blanch.

Harvesting

Leeks survive the harsh winter temperatures especially frosts. They are lifted as and when they are needed and they store well in sand or the fridge.

To lift a leek, ease the soil around the stem with a fork and shake off any unwanted soil. Take indoors and freeze if needs be. Clean and slice lengthways and store in the freezer for up to three months.

If one of the plants bolts and produces a seed head, remove this as quickly as possible. Use the leek as soon as possible. Plants going to seed are caused by early sowings or when growing conditions are poor.

Preparation For Cooking

Ensure all soil and sand in removed. It’s one of the banes of modern cooking to have grit in cooked vegetables and leeks are shocking vehicles for this.

Disease Issues

Leek Moth

The leek moth is problematic. Adult moths lay eggs on the plant and the caterpillars burrow in causing rotting in the stem. The affected leeks must be destroyed. Prevent occurrence by covering the plants with horticultural fleece which prevents the moth landing. There are leek moth traps available.

Leek Rust

If you see orange pustules and leaves with orange streaks then you have rust. Most leeks survive the condition but it becomes a severe problem as the disease takes hold. Reduce the amount of nitrogen in the soil prior to planting and apply some sulphate of potash (potassium sulphate) in the summer.

Onion White Rot

All members of the onion family including leeks are prone to this disease. It is a fungal issue which causes the leaves to wilt and the roots to rot. There is no cure and worse still, no members of the onion family can be grown in the soil for many years (at least five). Prevent the disease by ensuring any added soil is free from the rot and that no further contamination can be generated with boots and spades, or indeed any gardening equipment.

Thrips

A pain!

Varieties And Cultivars

A number of varieties are available and they can be divided into three main groups based on time of maturing:- early, mid-season and late.

The early types are ‘Early Market’, Prizetaker’ and ‘The Lyon’ which are very reliable and used from September to November. Mid-season varieties include Musselburgh and Watson Mammoth which are exceptional for November to January. The famous late varieties include ‘Yates Empire’, Royal Favourite’ and ‘Winter Crop’.

Leeks are grown as exhibition vegetables, especially ‘Prizetaker’ because most shows are held between August and November.

cv. Autumn Giant 2 – Argenta’ – A very large leek variety with extremely heavy stems. It will provide a huge crop when sown thinly. This variety matures in October but will withstand extreme cold and even be harvested right up to May. Excellent for wearing as a symbol at Welsh rugby matches.

cv. ‘Belton F1’ Wt. of 6 stems is 2.025kg, stem length (28cm), blanch length (8.5cm), diameter (2.6cm). Blue-green leaves. Good uniformity, solid stems with good length. Stands well without deterioration. Find at DT Brown seed suppliers.

cv. ‘Blauwgroene Winter – Bandit’. AGM (H5) 2009 A winter and spring type with blue-green flags with a reasonable blanch length.

cv. ‘Bleu De Solaise’. The ‘Blue Winter Leek’ is a very old French variety that is resistant to cold weather and turns darker when it experiences a hard cold frost. Grow for late autumn and early spring harvesting. Available from Real Seeds.

cv. ‘Carlton F1’. This is an early variety which is ready from August onwards but will stand until October if needed. The stems are long, with a good length of white. There is little waste and no ‘bulbing’ which comes with other hybrids.

cv. ‘Kenton’. A late-season variety providing medium-length shafts which are harvested up to early Spring. (DT Brown).

cv. ‘Musselburgh’. One of the standard cultivars with thick and short shafts. It is noted for its hardiness and reliability. Well known !

cv. ‘Northern Lights’. A lovely variety for the garden because of its highly distinctive purple leaves. It is very hardy in extremely cold weather. (Available from Dobies and Suttons).

cv. ‘Oarsman’ AGM (H5) 2002. A surprising winter to spring hybrid producing a good yield of stems.

cv. ‘Stamford’ – Early. AGM (H4) 2015.

cv. ‘Sultan F1’ One that takes over from Carlton F1 in November so the ideal Winter leek. It is slender with dense shanks which can be pulled right through to March. High yielding with a fine flavour.

cv. ‘Tornado’. A variety that is a very heavy cropping variety producing an abundance of erect plants with medium green foliage. Great for full sized leeks but also for baby leeks. Is available as seeds and as partly grown for use in tower growing systems. 

cv. ‘Zermatt’. A variety used for baby leeks but can be grown to full maturity. Ideal for containers.

Purchase your leek seeds here.

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