Originally grown BC, in the Mediterranean areas, including Egypt and Mesopotamia, it is one of the most widely grown vegetables in Allotments. Also, it is one of the few hardy vegetables available in the Winter and early Spring, if you grow the right varieties. Some of the newer so-called Winter varieties, are not proving to be hardy in cold and wet winters in the Glasgow area, with the leak stems turning into a rotten mush. After carrying out an inspection on many allotments, it was clear that only the old variety, Musselburgh, was standing up to extreme conditions. There are also Autumn and early Winter varieties of leeks. Further South, a new pest is causing damage to Leeks.
While you can buy seedlings for transplanting, you run the risk of bringing in diseases or pests with the soil. However, It is quite easy to grow your own leeks from seed.
Sow in deep boxes in January or February in a cool greenhouse or frame, and grow them on in cool conditions, and keep well watered. During April move the box outside to harden off. When the Leek seedlings are about 30 cm tall, they are ready to transplant into a deep, fertile bed. Use a dibber to prepare individual 20 cm deep holes, 20 cm apart, with the rows about 30 cm apart. Take the individual well grown seedlings and place at the bottom of the holes. Do not backfill the holes with soil. Instead with a watering can, fill the holes up with water. This dislodges enough soil to anchor the seedling to the bottom of the holes. Contrary to some advice, it is quite unnecessary to trim the tops or the roots, which only serves to check the growth.
Keep the Leeks weed free and well watered in dry conditions. It is possible to blanche the stems of the Leeks by drawing up the soil around the Leeks. Most people do not bother to do this as there is a big risk of getting soil in between the leaves of the Leek which makes it more difficult to prepare for eating.
Leeks are biannual plants. This means that they grow during the first year and flower in the second year. The flower is quite spectacular being a ball of flowers some 1.5 m above ground. However, as soon as the tough flower stalk starts to grow in the second season, the Leek is no longer much use as food and a few Leeks may be wasted.
Harvest as necessary in late Autumn and early Winter for the early Leeks. Harvest throughout the Winter and early Spring for the hardy over wintering varieties.
Storage. They are best used fresh, but they will keep for a week or two in the fridge crispator. For longer storage it is possible to clean and dice the leeks before freezing.
Pests and diseases There is not usually a problem in the North of the UK. Even slugs and snails leave them alone. Rust, (red spots) can affect the leaves but it is not usually a serious problem and can be ignored.
Some Leeks in the South of the UK are now being infected with two new pests.
Yellow green caterpillars of the Leek Moth can appear in May and June and again in August to September. The latter attack is likely to cause most damage when the caterpillars eat into the leaves and shafts of Leeks. The caterpillars eventually pupate in net cocoons to continue the cycle. The affected Leeks are likely to rot.
Larvae of a new pest, the Allium Leaf Miner, are now found in the West Midlands. Eggs hatch out in March and April and again in October and November, leading to cream coloured larvae which burrow into the stem of the Leek.
As these pests cannot be attacked with pesticides, you can only control them by using barrier methods, such as using a mesh.
Suggested varieties for Autumn Leeks.
King Richard. An early, tall, full flavoured Leek, but as it is not fully hardy in the North of the UK, it should be eaten before hard frosts.
Suggested varieties for Winter Leeks.
Musselburgh. The one that can survive during Scottish Winters!
Suggested leek varieties to use as baby leeks & to grow on to full size
Leek offsets are sometimes formed in second and subsequent years of growth if the leek plants are left undisturbed. Theoretically, the offsets could be separated from the original leek, and replanted. It is not worth the effort as it is easier to sow each year from seed. The original leek dies after flowering and producing seed.
Reproducing leeks by bulbils, “pips or grass”. This is the method by which super specimens such as “show leeks” are usually grown. These show leeks are specially selected strains to produce giant leeks. You can see the principal of this method if you allow one of your leek plants to form a flower head in the second year( they are bi-annuals). Give them the following treatment, and instead of forming leek seed pods, they will form green shoots which can be planted up. It is not what you would expect to happen, but nature is very complex and surprising! Leeks produced by this method will be genetically the same as the original plant.
Allow the flower buds to form and then using small scissors, cut off all the individual buds. The leek plant then compensates for this treatment, by trying to reproduce itself by forming bulbils, pips or grass, as shown in the photos.