Summer Leek and Winter Leek

In short: Summer leeks grow faster, need about 150 days and must be harvested before the first frosts. Winter leeks need about 200 days, are frost-resistant and overwinter in the ground, with thicker stems that can exceed 6 cm in diameter. Autumn varieties sit in between and are harvested in October and November.

Garden leek (lat. Allium porrum) is a plant from the Amaryllidaceae family. It belongs to the botanical genus garlic, just like its close relatives garlic and onion. Garden leek and its summer, autumn and winter varieties were bred from the wild species Allium ampeloprasum. The original homeland of leek is southern Europe, southwestern Asia, southern England and Persia. Leek cultivation has a long tradition, it was grown by the Egyptians, Greeks and Romans in ancient times. Nowadays, leek cultivation is still popular. Thanks to breeding, growers can choose from a large number of varieties.

Garden leek - plant description

Garden leek is a perennial plant, but it is usually grown only as an annual, winter varieties as biennials. The leek bulb has a cylindrical shape. The stem is usually robust and can be covered with leaf sheaths up to halfway. The leaves of garden leek are simple, sessile to the stem. Garden leek has bisexual flowers grouped in an inflorescence botanically called an umbel. The inflorescences are supported by a spathe. Parts of the inflorescence are bulbils, as an organ suitable for vegetative propagation of leek. The fruit of garden leek is a capsule.

Growing leeks

Leeks can be grown from seed or from seedlings. The yield from plants grown from seedlings is usually higher. It is advisable to start sowing summer leek varieties as early as possible. They can be sown in a propagator as early as January. The ideal temperature for germination is around 18°C. The germinated seedlings are very tiny, thread-like. They are planted in outdoor beds in April, when there is no longer a risk of frost. Planting is carried out at a spacing of 30 x 10 cm. Summer leeks are harvested in August and September. Autumn varieties should be sown approximately from mid-February to mid-March. Pre-grown seedlings are planted in beds in mid-June. Harvesting of autumn leek varieties takes place in October and November. Winter leek varieties are sown latest, they can be sown as late as April. Plants reach sufficient size for planting in beds in June. These leeks can be harvested from March to approximately May of the following year. All leek varieties are sown to a depth of approximately 1 cm. Seedlings ready for planting should have a thickness of approximately 3-5 mm and 3-4 true leaves. Long roots should be shortened to a length of around 2 cm and leaves by about a third. Planting is most convenient in pre-dug furrows. During the growing season, it is necessary to regularly loosen leek beds, weed, fertilize, water and treat against diseases and pests. The most effective is fertilizing with complete fertilizers such as Cererit or NPK fertilizer. Regular earthing up should not be forgotten, so that the blanched part is as large as possible.

Suitable Growing Location for Leeks

Leeks can be grown even in cooler locations and are not overly demanding. They thrive best in lighter, loamy-sandy soils that are well-fertilized and retain sufficient moisture. Leeks are a second rotation crop, so they should be grown after crops that were heavily fertilized with farmyard manure (potatoes, brassicas, and cucumbers). During the growing season, approximately 13 g of nitrogen, 10 g of phosphates, and 28 g of potassium salt per m² should be added to the soil. This fertilizer dose should be applied to the leeks in three separate applications. The first feeding, which is applied before sowing, should be richer in nitrogen and contain less potassium salts and phosphates. The second wave of feeding should ideally be carried out after approximately three weeks. The final, third feeding is applied when the plants have already fully developed some leaves. The third dose of fertilizer should contain the highest proportion of potassium and phosphorus, while nitrates should be at their lowest.

Diseases and Pests

In recent years, the most common pest on leeks has been the leek moth. This pest produces 2 generations per year under our conditions. First-generation leek moths attack leek plants at the turn of April and May, while the second generation begins causing damage at the end of August and beginning of September. The simplest prevention against leek moth is to cover the leek crop with non-woven fabric during the risk period. For this method to be effective, the edges of the fabric must be buried in the soil to prevent pests from penetrating underneath. If this has already happened and the pests have attacked the leeks, it's time to proceed with chemical protection, for example using Decis. Other pests that may appear on leeks include leek aphid, stem nematode, thrips, and allium leaf miner.

Summer Leeks

• Have a shorter growing period - approximately 150 days.

• Must be harvested no later than the arrival of the first frosts.

• Grow faster and can reach heights of up to 1 m.

• The edible part (blanched) is longer.

• On average, thinner than winter leeks.

Winter Leeks

• Longer growing period - approximately 200 days.

• Frost-resistant, overwinters without problems.

• Grow more slowly and are more robust.

• The edible part is thicker - can exceed 6 cm in diameter.

• Must be harvested before they resume growth in spring and produce flowers.

Most Commonly Grown Leek Varieties

• Summer leek variety Golem is fast-growing and, under favorable conditions, can reach up to one meter in height. The edible part is longer compared to other varieties, but it is somewhat thinner, averaging around 4 cm in diameter. The vegetation period of this variety is approximately 155-165 days, so it's advisable to sow it from January onwards in prepared trays. Golem leek is transplanted to the garden bed from April. It thrives in sunny locations with moderately heavy, nutrient-rich soil.

• Starozagorski Kamuš is a traditional summer leek variety with high yields. It can grow up to 50 cm in height. The ideal location for growing this leek variety is a site with heavier, deeper soil containing sufficient nutrients. When growing in lighter soils, regular watering is necessary to prevent the soil from drying out excessively.

• De Carentan 2 leek is a late winter type of leek with medium-length straight stems. The advantage of this leek variety is its excellent frost resistance. De Carentan leek requires cultivation in moist, loose soil rich in nutrients.

• Winter leek variety Elefant is suitable for autumn harvest, but it can easily be harvested until the spring months. Its leaves are dark green in color. The length of the edible part can be extended through regular fertilizing. Seeds of this leek variety can be sown directly in the garden bed from March to April, while seedlings for pre-cultivation need to be sown in the second half of February.

• Winter leek variety Tango is intended for autumn harvest but can be harvested until the spring months. Its leaves are more rigid and robust. Tango variety grows more slowly, with a vegetation period of approximately 180-200 days.

• Other frequently grown leek varieties include autumn leek Terminal and winter leek Winner.