The leek, already known to the ancient Egyptians 2000 years before Christ, was even known, according to some scholars, to the Celtic people of much more remote antiquity. The leek is an herbaceous, biennial plant, belonging to the Liliaceae family (such as garlic and onion). Its cultivation and consumption was greatly spread during the Middle Ages. The parts that are used are the bases of the foliar sheaths (the stem is, in fact, very small and it is the small, fleshy disc that lies between the leaves and the roots). The nutritional value is only 29 kcal/100g of fresh product, but it contains good amounts of iron, calcium, phosphorus, vitamins B1, B2, PP, and C. From a health perspective, the leek is recognized for its good tonic, nervine, diuretic, laxative, and antiseptic properties and is recommended for dyspepsia, anemia, rheumatism, arthritis, gout, and urinary diseases.
Preparation of the soil should be done by adding about 3-5 kg / sqm of organic compost to which one can add 50 g / sqm of superphosphate and 50 g / sqm of potassium sulphate. The seedlings can be transplanted in March, when there is no further danger of frost. The distances to maintain when planting will be about 40 cm. between rows and 20 cm. on the row.
The most severe hazards result from infections by pathogenic fungi derived from the soil, such as Fusarium culmorum and Pyrenochaeta terrestris, which attack the rootage. Other fungi harmful to the foliage are rusts (Puccinia porri and Puccinia allii), Peronospora of the leek, and Alternaria of the leek. For the former, wet soils and stagnant water must be avoided. For the latter, mild interventions with copper-based products may be required. Among the animal parasites, those to single out are the leek moth (Acrolepia assectella), the onion fly (Hylemia antiqua), the thrips (Trips tabaci), and the stem nematode (Ditylenchus dipsaci). These insects can be fought with natural pyrethroids or attractive traps.