Kohlrabi

The kohlrabi (Brassica oleracea var gongylodes L.), also top kohlrabi, Oberrübe, Rübkohl and Stängelrübe is a vegetable. He is one of the many cultivated varieties of vegetables cabbage. Used is the thickened, aboveground stem axis ( sprout tuber) here. The term rabi is derived from the Latin name rapa, turnip and kohlrabi = rupum thus means swede.

Features

Kohlrabi is a biennial plant, during the first year sprout tuber is formed, and in the second year of the stems with a branched inflorescence.

The tuber is compressed, thickened main stem of the plant. It arises at the second or third true leaf through primary radial growth of the stem axis. The shape of the tuber may be round, flat round or oval, the color of the shell whitish, white-green to bright green, reddish or purple. The diameter is depending on the variety 5-20 cm, or even more. The weight is depending on the variety and use between 100 g and 8 kg per tuber. Individual values ​​may not be much about it.

The leaves are long-petiolate, dark green, oblong ovate and more or less strongly serrated. They are covered with a bluish- white wax. The plants form a taproot.

Flower formation can be triggered by prolonged cold stimuli already in the two-leaf stage ( vernalization); also cause high temperatures to a Devernalisation.

Ingredients

100 g fresh weight of the edible portion of the tubers contain an average of 91.6 g of water, 1.9 g protein, 0.1 g fat, 3.8 g carbohydrates and 1.4 g dietary fiber. Minerals potassium (380 mg ), calcium (70 mg), phosphorous (50 mg), to give magnesium (45 mg ) and iron ( 0.9 mg). At vitamins are vitamin C (65 mg ), vitamin A ( carotene, 0.2 mg ), vitamin B1 (0.05 mg ), vitamin B2 (0.05 mg) and niacin (1.8 mg) available. The energy value is 103 kJ ( 24 kcal = ).

The taste of the kohlrabi is based on the content of sugar, fruit acids and mustard oil glycosides. The fruit acids malic acid and citric acid clearly dominate.

Kohlrabi leaves are opposite the bulb one about twice as high content of vitamin C, the content of carotene is 100 times as high, the calcium and iron 10 times as high.

Cultivation

There are quite a few varieties, in Germany 30 white and 14 blue kohlrabi varieties. It set itself augmented by hybrid varieties. Important properties are: yield, low tendency of tubers for Lignify and bursting, fast growth and low tendency to bolting. The varieties that provide the largest tubers are ' giant ' and ' super melting '. The varieties differ in color (white and blue) and the growing season; white turnip varieties require less culture time as blue varieties. If there is insufficient planting distance is kohlrabi, mainly due to lack of light, cylindrical shapes from Knoll.

In the EU, there are two grades:

• Kohlrabi Class I must be well formed, with no cracks and no skin defects. The root is cut off close to the bulb, with kohlrabi without leaves, the leaves are cut off close to the tuber. The minimum diameter (according to the maximum diameter ) is for blowing kohlrabi with leaves 30mm for outdoor kohlrabi with leaves 40 mm, for kohlrabi without leaves 50 mm. In addition there are sorts: with leaves 40-55 mm, 55-70 mm and 70 mm; without leaves 50-70 mm and over 70 mm.
• Slight defects of shape and color are acceptable for Class II, as well as minor cracks and damage. Sizing is not compulsory. The minimum diameter is 30 mm for kohlrabi with leaves, without leaves 40 mm.

Outdoor

Regarding the soil Kohlrabi is sensitive to large changes in soil moisture, this leads to a bursting of the tubers. The climate has kohlrabi a wide amplitude and grows well in Central and Western Europe. In summer and autumn range from low temperatures, when young but he needs heat.

In the crop rotation longer cultivation periods are desirable to other cruciferous vegetables. Short crop rotations increase the risk of soil -borne diseases, particularly of clubroot. Other claims regarding the previous crop is not kohlrabi. Similarly, all kinds of vegetables are suitable as following crop. Kohlrabi makes no special demands on the nitrogen supply; excessive nitrogen fertilization can easily lead to elevated nitrate levels in the tuber.

When kohlrabi there in Central Europe early, summer and autumn production in the field, producing for the fresh market and the processing industry. Kohlrabi has a short development time and is often grown as a preliminary, intermediate or subsequent crop. Central European production can supply the market between May and November with fresh produce. The cultivation for the fresh market is mainly carried out in gardening vegetable farms, crops for industrial processing, however, mostly on farms ( field vegetables ).

Widely used is the cultivation of young plants and the subsequent planting in the field. The plant densities vary between 16 to 17 pieces per m² in spring cultivation and 8 to 10 pieces per m² in the later varieties. In spring the plants for earliness are partially covered with single or double slides. The yields are in the early years growing at 20 to 30 tons per hectare, in summer and autumn at 45 to 70 tons per hectare. The harvest takes place in fresh produce by hand. Large kohlrabi for industrial processing can be salvaged with cabbage harvester with special turnip - cutter.

Early varieties can accumulate bad, the shelf life of only two to three weeks. Autumn kohlrabi can be stored for several months without foliage.

Greenhouse

The growing of kohlrabi in a greenhouse is particularly widespread in the Netherlands, Germany, Switzerland and Austria. In the greenhouse, the culture is performed for harvest in winter. An diseases are downy mildew and black leg of importance only in poor ventilation. The harvest greenhouse kohlrabi with leaves, which indicates the degree of freshness.

Diseases and Pests

Viral diseases have no economic significance, the cauliflower mosaic virus in Kohlrabi (s: cauliflower mosaic virus ) occasionally occurs. The bacterial and fungal diseases are essentially the same as for cabbage and cauliflower: particularly clubroot and downy mildew. Especially with kohlrabi occurs, the fungus Cylindrosporium concentricum, leaves and tuber attacks. The leaves fall early on, the fabric is gray-green, on the tuber form dark gray stains, later callus tissue.

Among the animal pests are the same name as in head and cauliflower. Significantly outdoor farming is the Great Cabbage stem weevil ( Ceutorhynchus napi ). The eggs laid lead to a disruption of the tubers.

Use

The young tubers are peeled and cut into slices or chunks cooked or steamed - as a side dish, mashed potatoes, in stews and soups, for fillings and casseroles. Young leaves can be used like other leafy vegetables. In parts of France, the tubers are planed and conserved as sauerkraut. Also known as Raw kohlrabi is suitable.

Cultural History

The origin of the kohlrabi is unclear. Often referred to areas of possible domestication are the Mediterranean and Central Asia. Also unclear is the date of creation.

Secure evidence is there only from Europe in the 16th century. From this period there are clearly identifiable drawings in herbals. From the 18th century comes first evidence of flat round tubers. In the German-speaking area of kohlrabi was particularly widespread in the 19th century. He is widely regarded as a typical German vegetables, so that the German name was adopted in several other languages ​​, such as into English, Russian and Japanese.

In the " continuation of the general Teutonic garden magazine" of 1815 are enumerated by the white turnip varieties of small early ( Vienna ) kohlrabi, the large glass kohlrabi and the mean green kohlrabi, from the blue and red varieties of the early blue glass kohlrabi and the late blue kohlrabi. Today the most famous in Germany varieties bog are white engine, Vienna Blue Glass and Blue Bacon.

Documents

• Georg Vogel: Handbook of special Gemüsebaues. Verlag Eugen Ulmer, Stuttgart 1996. ISBN 3-8001-5285-1, pp. 304-323
• Sachweh Ulrich (Editor): The Gardener, Volume 3, nursery, fruit growing, seed growing, vegetable growing. 2nd edition, Ulm, Stuttgart 1986/1989, ISBN 3-8001-1148-9, p.221