Leek is a popular vegetable with many valuable nutritional properties. Together with garlic and onions, it belongs to the group of allium vegetables. Leeks don’t form a large bulb like an onion. The edible part of the plant are the closely overlapping leaves. The lower part of the leaves is white and the upper part is green. The white part has a more delicate taste than the green part. The ends of the leaves are flat, with a leathery texture. They are much less tasty than the lower part. The aim of leek cultivation is to have the longest possible white part – for consumption.
The genetic potential of the variety and the cultivation technique influence the quantity and quality of the yield.
A distinction is made on the basis of the date of the harvest:
- Early and medium early varieties – summer and fall harvest. They have a shorter growing season than late varieties. They grow faster and have a milder flavor.
- Medium-late and late varieties – are usually intended for harvesting in winter and spring of the following year (late varieties of leek can withstand temperature drops as low as -15°C, so many varieties overwinter in the ground).
Two methods of growing leeks are used: from seeds and from seedlings. Sowing the seeds directly into the soil – in practice, this method is rarely used because the seedlings are very small and can be easily damaged by rain.
GROWN FROM SEEDLINGS
Leek emerges 10–20 days after sowing (with optimum temperature in the range of 15–20°C). Seedling production takes 8–12 weeks. When the seedlings are 15–20 cm high, they can be planted in the ground. The seedling must be hardened before planting in the ground. Leek yields best on moderately compact, sandy-loam soils with a high humus content. It prefers a regulated soil reaction. The pH should be between 6.5 and 7.0. The location for cultivation should be sunny. Leek is a plant that has high nutritional requirements. It has a strong root system, but most of its roots are located at a fairly shallow depth, with only a few individual roots growing deeper. Plants of leeks respond very positively to organic fertilization. It also requires intensive and rational mineral fertilization, adapted to the needs and abundance of the soil, determined by soil analysis.
Apart from basic soil fertilization, foliar fertilization is a standard. Its main advantage fertilization is the quick and effective supply of the most-required nutrients to plants at particular stages of development.
- Phosphorus, delivered by foliar application, after adaptation of seedling, has a beneficial effect on the rate of growth of the leaves. It also supports the development of the root system (GROWON® or PLONVIT® FOSTAR or PLONVIT® PHOSPHO).
- During intensive growth of leaves, it is especially important to have an optimal supply of nitrogen (PLONVIT® NITROMAG or PLONVIT® NITRO).
- Potassium is very important in the cultivation of allium vegetables. It is responsible for production and transport of photosynthetic substances to the harvestable plant parts. Also, it regulates water management of plants and sugar biosynthesis (PLONVIT® KALPRIM, PLONVIT® KALI).
- In the fertilization of leek, magnesium should be taken into account (MIKROKOMPLEX®), as well as calcium (OPTYCAL®, PLONVIT® CALCIUM TURBO).
- In the cultivation of leeks, it is advisable to feed them prophylactically with the AMINO ULTRA® HORTI micronutrient fertilizer, during the period of intensive growth. Among the micro-nutrients, the most important are: iron (AMINO ULTRA® Fe-20 or MIKROCHELAT™ Fe-13) manganese (AMINO ULTRA® Mn-22 or MIKROCHELAT™ Mn-13), zinc (AMINO ULTRA® Zn-24 or MIKROCHELAT Zn-15) and molybdenum (MIKROVIT® MOLYBDENUM).
- For ensure large yield quantity and good quality – very important is biostimulation. The foliar applications of TYTANIT®, OPTYSIL®, AMINOPRIM®, PLANTICINE® may stimulate plants for better growth and yield and for improvement of tolerance to abiotic (weather conditions) and biotic (disease and pest appearance) stresses, as well as the capability of accelerating the recovery of plants after the occurrence of stressful conditions.
- Particularly noteworthy are the highly alkaline line of fertilizers ALKALIN: ALKALIN™ K+Si, ALKALIN™ KB+Si, ALKALIN™ PK 10:20. Alkaline pH of fertilizer solutions activates the immune factors of plants.
- It is important to reduce nematodes in leek crops. For this purpose, the use of BACTIM® RECEPTOR is recommended. It is a bioproduct especially advisable for sites threatened by nematodes. This product can be used prophylactically as a single dose or several times depending on the pressure of nematodes. On nematode-free sites, it is worth using BACTIM® VIGOR. This product positively affects the size and quality of the crop. It reduces the susceptibility of plants to abiotic and biotic stresses.
INTERMAG’s wide range of products, allows you to develop your own individual foliar fertilization and biostimulation program, considering local soil conditions, crop intensity, stage of plant development and availability of various products.
