Popular Varieties: King Richard, Goliath, Cortina
Store At: Cool, 5-10°C
Comes From: England, Temperate Countries
Seasonality: Autumn to Spring
In the same family as onions and garlic, leeks are long tubes of many layers, as opposed to bulbous formations of layers. They are blanched (made to turn white) by pulling up soil around the plant, which excludes light and prevents the formation of chlorophyll.
Leeks are split into two types; summer leeks and overwintering leeks. Summer leeks are grown from early in the year and mature quickly, usually forming smaller, thinner leeks with a milder taste. Overwintering leeks can be started later, and mature slower, forming a stronger flavour.
To choose a leek in the supermarket, it should be firm and straight. The leaves should not be wilted or yellow. Try to pick a leek that is less than one and a half inches or 3cm in diameter, because when they get bigger, they get fibrous and tough.
Fresh leeks should be stored in the refrigerator, unwashed and untrimmed. Wrapping them inside a plastic bag can help to retain moisture, and they can be stored in this way for one to two weeks.
Leeks were first popular with the Ancient Egyptians, Romans and Greeks, who together contributed largely to the spread of leeks across Europe from their presumed native Central Asia. They were held in high regard by the Greeks and Romans for their medical benefit to the throat, in particular making a voice stronger and clearer.
The Romans probably introduced leeks to England and the United Kingdom, where they did well because of the favourable climate due to their ability to withstand cold weather.
Leeks have long been the national emblem of Wales, which goes back to a battle the Welsh army fought against the Saxons; they put leeks in their caps to distinguish them from their opponents. They won the battle, and from then on the leek has played an important part in the imagery associated with Wales.
Leeks are fairly limited in their use; there are some varieties with blue green leaves that can be use for ornamental purposes, but this is limited, and the only other use is cooking. The edible part of leeks are the lower white part of the stalk, and the light green part. The dark green leaves should not be eaten.
They are quite versatile in cooking however, with a milder and sweeter flavour than onions. They can be boiled, steamed, cooked in stews or casseroles, cooked with pasta, or wrapped in pastry and baked. Leeks are good for adding to soups, and young leeks and be sliced or chopped and used raw to substitute for spring onions in salads.
Leeks are a great addition to the diet; they have many of the dietary benefits of onions, including reducing cholesterol and helping combat the offset of diabetic heart disease, and also to help lower blood pressure. Allium vegetables have also been shown to reduce the risk of prostate and colon cancer if taken as little as two to three times a week. Leeks do contain smaller amounts of these benefitting compounds than onions or garlic do, so larger amounts of leeks are required for the same effect.
Leeks are quite demanding, as you would expect from something that’s going to be in the ground for up to and possibly over a year. While they’re slow growing, they’re worth the wait.
For best germination, seeds should be sown under cover, at temperatures of around 12-16°C, in late winter. This will give seeds the best chance at germinating (they need a minimum of 7°C to germinate) – since they’re going to be growing for a while, make sure you sow plenty to ensure you get enough to grow on. The seeds can be sown in trays, pots or modules of compost. When the seedlings are growing, and have two true leaves to replace the seed leaves, they should be planted about 2 inches or in individual pots.
If starting later in the season, the seeds can be sown directly into the vegetable plot or a seedbed, but it is recommended to warm up the soil using cloches, black plastic or horticultural fleece. If sowing directly into the ground, sow the seeds 1 inch deep in rows 12 inches apart, and thin the seedlings when they have two or three true leaves.
Sowing and growing the seeds in modules or plant pots is particularly successful – there is no need to thin out seedlings, and you can easily control the spacing between plants when planted out.
The ground which leeks are to grow in must be well prepared; it must be rich in organic matter, to aid moisture retention, and it needs to be fertile, so plenty of organic matter should be dug into the ground the winter before planting, to allow the nature time to break it down and work it into the soil properly. While the soil should be moisture retentive, leeks need good drainage, and will crop poorly if the ground becomes waterlogged or is heavy.
Since leeks will be in the soil a long time, it’s important to enrich the soil with nitrogen to aid in leaf growth; use something like general fertilizer (bedding plants or tomato feed has low concentrations of nitrogen in), or fish, blood and bone, or ammonium sulphate to increase the nitrogen content of the soil. This should be done a couple of weeks before planting, to allow the nutrients to spread into the soil, but not long enough to allow them to be used up or leeched out.
Leeks should be transplanted when they are 6-8 inches (15-20cm) tall. The leaf tips should be trimmed back a little if they drag on the ground, but don’t trim the roots as sometimes recommended. Give the soil a good watering beforehand if its dry, and plant the leeks 15cm (6 inches) apart in rows that are 30cm (12 inches) apart if you want a high yield of decent sized leeks. If you want a higher yield of slim leeks, plant them about 3-4 inches apart.
To plant the leek, make a hole about 6 to 8 inches (15-20cm) deep with a dibber (for example a broom handle), drop the plant in, and water it well, which will wash some soil from the sides of the hole to fill it in, but don’t bother filling it in anymore. Leeks planted like this will be more drought resistant and soil is less likely to fall between the leaves, so you don’t get a gritty taste in your mouth when eating them! Planting them deeply like this also ensures you’ll get a well blanched stem.
An alternate method to plant leeks is to plant them about 3 inches (7½cm) deep, and pull the earth up around the stem several times throughout the season, as is done with potatoes. Be careful not to get any soil down the leaves when earthing up.
Early varieties will be ready to harvest from early to mid-autumn, mid season varieties can be pulled from early to mid winter, and late varieties from early to mid spring. Lift the plants carefully, preferably using a garden fork and dispose of any dead leaves to prevent spread of any disease.
Leeks suffer from many similar diseases to onions, including Leek rust, which shows up as orange blotches on the leaves during summer. Slugs and snails can also be damaging, with the latter easily disposed by many methods, including my favourite, off the end of my foot at the end of a run up! Leaf rot is also a possibility, but can be controlled with fungicide and maintaining good air circulation between the plants (i.e. not planting them too closely together).
- Leeks on Wikipedia
- HungryMonster Leeks Article
- WH Foods Link on Leeks
Not many people will know varieties of leeks, unless you grow them, since they are not typically labelled in supermarkets. So, for the growers amongst you, some popular ones are King Richard, Cortina, and Bleu de Solaise.
An early variety, King Richard is a high yielding leek with a fairly mild taste. Itâ€™s also good for growing close together for mini or baby leeks.
Bleu de Solaise
Bleu de Solaise is a French winter variety of leek, and can be harvested all the way until Spring. The leaves are tinged blue, and it can also be grown for ornamental purposes.
Cortina is a late leek and can be harvested throughout the winter, but only provides a moderate sized yield.
Goliath, and a close relative, Autumn Mammoth 2, can be harvested early, from late autumn, all the way through winter until mid-spring. They are high yielding varieties of leeks, with thick stems.