Brassica oleracea L. var. capitata Plenck
Brassicaceae (sin. Cruciferae)
History and origins
The main center of origin of head cabbage is an area that includes Eastern Europe and Asia Minor.
Its seems to derive from Brassica oleracea L. var. acephala DC., “headless” cabbage.
Ancient Greeks held the first types of wild cabbage in high regard and thought they were gifts from the gods.
The Celts and ancient Romans spread cabbage all over Europe; in fact, the Latin term Brassica comes from the Celtic word bresic, meaning cabbage.
Spanish settlers brought cabbage to the New World and the natives adopted the new crop at once.
Leaf cabbages (head and Savoy cabbages) were introduced to North America (Canada) by the French explorer Jacques Cartier in 1541 during his third voyage.
Most cultivars used in the United States today derive from the types originally grown in Germany, Denmark and the Netherlands.
Red cabbage contains anthocianins with antioxidant properties (anti-free radicals).
Diffusion and importance
Stem: erect, with short internodes, ligneous at the base.
Leaves: simple, smooth, from green to light green (f. alba, white cabbage) and purple red (f. rubra, red cabbage), which during the first year, form a compact head (the edible part) in the center, weighing on average 1-4 kg.
Inflorescence: forms in the second year after a period of low temperatures (vernalization) which is necessary for flower induction. Inflorescences are arranged in bunches on the main stem; flowers have white or yellow petals; flowering starts in April-May and lasts 30-40 days; fecundation is mostly allogamous and pollination is entomophilous.
Fruit: it is a lengthened siliqua (1-8 cm) containing up to 25 seeds; seeds are globular, red-brown, with a diameter of 1.5-2.5 mm, weighing 2.5-3.5 mg (1 g consists of about 350 seeds), with an average longevity of 4-5 years.
Climate and soil requirements
Head cabbage has low thermal requirements.
The minimum temperature for germination is about 6° C, the optimum 20° C; at this temperature, germination begins after 3-4 days and is complete in about 10-12 days.
For vegetative growth, the minimum temperature (zero vegetation point) is around 5° C, with optimum temperatures between 15-18° C.
Head cabbage has an elevated resistance to cold which allows it to withstand minimum temperatures of –10° C during the growth phase; when the “head” is totally differentiated, its resistance decreases and can be damaged by cold.
High temperatures after transplanting or when the head is totally formed promote physiopathologies (bolting and head splitting) with depreciation of the product.
It is able to adapt to different types of terrain, but it prefers medium-textured, deep, fertile soil; optimal pH is between 6.5 and 7.5. In acidic soil, it is prone to club root (Plasmodiophora brassicae).
It has medium tolerance to salinity.
In non-specialized horticulture, the head cabbage is a typical intercropping vegetable, often following wheat; it can be followed by a rotation crop with a spring-summer cycle.
In specialized horticulture, it follows spring-summer cultivations (pea, potato, tomato, zucchini). In the southern regions and in some areas of central Italy, the production cycle can be in spring-summer as well.
For phytosanitary reasons, head cabbage should never be planted in the same soil where it or other crucifers have grown for at least three years.
Varieties and/or commercial types
– head color: white or red;
– cultivation cycle period: spring, summer, autumn-winter;
– cultivation cycle length: 60 to 140 days from transplant;
– morphobiological uniformity: standard varieties, F1 hybrids.A good head cabbage cultivar must have the following characteristics:
– well-defined cycle length according to the class of precocity;
– regular head conformation;
– compact growth to increase cultivation density;
– resistance to cold, to bolting caused by some physiopathologies (e.g. splitting of the head) and tolerance to biotic adversities.Hybrids have a higher production capacity, morphobiological uniformity and resistance to disease than standard varieties, but obviously, their seeds are more expensive (approximately, 1,000 hybrid seeds cost about 15 € and seeds of a standard variety about 3 €).
Fundamentals of cultivation practices
Head cabbage can be sown directly in the fields or more often, is transplanted; it takes about 1 month for the plant to grow enough to be transplanted.
In Italy, planting takes place between March and October and is harvested, depending on the precocity of the cultivar, after 2-5 months; in warm and dry areas, it develops better in autumn and winter (the seasons in which it is most often eaten in Italy).
Planting density is 3-6 plants/m2 in rows 60-80 cm apart.Nutrient and water requirements
Head cabbage has high nutritional requirements; it especially needs nitrogen and potassium (about 150 kg/ha of each).
Meeting the water requirements of the cultivation is essential for both the quantity and quality of production; in Mediterranean countries, most of its water requirements are generally met by copious rains in the autumn and winter months. Irrigation is necessary after transplant to help the young plants take root, and during the first month of their cycle if rainfall is insufficient; in cultivations with a spring-summer cycle, irrigation is necessary during the entire cultivation cycle.Cultivation practices
Mechanical hoeing can be carried out during the first phases of the cycle, before the foliage “closes” the spaces between rows in order to:
– control weeds;
– maintain the aeration of soils with a tendency to form a surface crust.
Hilling must only be done when plants are irrigated from lateral furrows, otherwise it is an uncommon practice.
Harvesting can be done in any period, according to the time of planting and the length of the cultivation cycle of the chosen cultivar.
Head cabbage can be eaten raw, cooked or preserved (e.g. it can be used to make sauerkraut or sour cabbage).
Cabbage for the fresh produce market is harvested manually by cutting the plant at its base and removing the outer leaves to leave only its central head.
The cabbage crops in large fields that are destined for sauerkraut production can be harvested mechanically.