Kohlrabi - Delicious Brassica Vegetable

In short: Kohlrabi grows best in moist loamy or sandy-loam soil with enough humus and does not need high temperatures. Early varieties need about 80–100 days, summer varieties 100–140 and late ones 130–170. Plant seedlings with three to four true leaves at about 30 x 40 cm, not too deep, and water evenly to prevent cracking.

Kohlrabi (lat. Brassica oleracea conv. acephala, var. gongylodes) belongs to the broad family of Brassicaceae plants (lat. Brassicaceae) together with cabbage, kale, collard greens, cauliflower and broccoli. All these cole crops were bred from the original wild cabbage plant (lat. Brassica oleracea). A common feature is their thickened stem. Kohlrabi has either a green or purple bulb. Green forms have the Latin designation var. alboviridis and blue (purple) varieties var. purpurenscens. Kohlrabi originates from the Mediterranean, from where it spread further to northern regions. Kohlrabi is a biennial plant, but in our conditions it is usually grown only as an annual for its bulb, which was formed by shortening of the stem and significant secondary thickening.

Growing Kohlrabi

The ideal location for growing kohlrabi is loamy or sandy-loam soils with sufficient amount of humus. The location should be rather moist, kohlrabi doesn't need very high temperatures for good growth. Growing is simple, however it is necessary to take into account what variety of kohlrabi it is. Early varieties have a shorter growing season (approx. 80 - 100 days). Early varieties are sown in February in prepared sowing devices. Summer varieties have a vegetation period of approx. 100 - 140 days, sowing is carried out in March and April. Late varieties of kohlrabi with a growing season of approx. 130 - 170 days are sown at the turn of April and May. Planting of grown seedlings with three to four true leaves should take place for early varieties in April, summer varieties are planted in the bed in May and June, late varieties must come to the bed no later than mid-July. Seedlings are planted in the bed at a spacing of approx. 30 x 40 cm. When planting, it is necessary to ensure that the seedlings are not planted too deep, otherwise they would not form the desired bulbs. It is advisable to cover early varieties of kohlrabi with non-woven fabric after planting, so that young plants are protected from possible ground frosts. Kohlrabi is a second-year crop plant, it does not tolerate direct manure fertilization. With excess nitrogen, bulbs do not form. However, before planting it is advisable to work 30 - 60 g / m² of industrial fertilizer e.g. NPK into the soil. Fertilizer should be applied to the soil in two doses - first at planting and second during vegetation. Late varieties are more demanding on nutrients. During vegetation it is necessary to keep kohlrabi beds free of weeds and regularly hoe them. Regular and uniform watering is important. White varieties are more sensitive and often crack as a result of improper watering. Kohlrabi plants are most commonly damaged by cabbage white butterflies, root-knot nematodes, cabbage moths, and four-toothed weevils. Of diseases, powdery mildew of brassicas and clubroot of brassicas occur on kohlrabi.

Most Commonly Grown Kohlrabi Varieties

• Early Kohlrabi Luna is a very early to medium-early variety characterized by tender flesh and high yield. It is intended for cultivation from pre-grown seedlings. It can also be grown in containers and is suitable for forcing by all methods. This variety requires moisture. However, it has been bred to be resistant to bolting, woodiness, and bulb cracking. The ideal location for this type of kohlrabi is a sunny site. The harvested kohlrabi are very firm with good flavor.

• Early Kohlrabi variety Cabbage Vegetables is a very early hybrid variety intended for forcing by all methods. It is very resistant to woodiness, cracking, bolting, and bulb overgrowth. The bulb of this variety is flat-round in shape, light green.

• Early Kohlrabi Kartágo F1 is a white kohlrabi variety with tender flesh, very resistant to woodiness and bulb overgrowth. It is suitable for forcing and for very early field cultivation, and can also be used for cultivation from summer sowings for autumn harvest.

• Other early varieties with white bulbs include, for example, early kohlrabi Korfu 1 and early kohlrabi Moravia.

• A purple variety of early kohlrabi is Blankyt. This kohlrabi has sparse foliage, with the advantage of high resistance to woodiness. The Blankyt variety can be grown throughout the entire growing season.

• Early purple kohlrabi variety Ballot F1 is a hybrid variety intended for spring and autumn field cultivation. It is very resistant to cracking, woodiness, and bolting to flower. A suitable site for growing this purple type of kohlrabi is a location with heavier soil rich in nutrients. Additional fertilizing during the season also has beneficial effects on yield, but be careful with nitrogen.

• Late Kohlrabi Troja F1 is a semi-early white hybrid resistant to woodiness and bulb overgrowth. The bulb is large, flat-round in shape. The flesh is very tender. This kohlrabi variety can be grown from spring and summer sowings. The site should be chosen rather moist, it can also be slightly shaded.

• Late Kohlrabi Gigant is suitable rather for feed purposes, has exceptionally vigorous growth, does not become woody and does not crack. The flesh is white in color, sweet in taste. This type of kohlrabi is suitable for direct consumption as well as for long-term storage.

• Late purple kohlrabi variety Violeta stores very well. The plants are of vigorous growth, kohlrabi can grow up to 600 g in size. The flesh is of good and tender taste, resistant to cracking.

Beneficial Effects of Kohlrabi

Kohlrabi is a source of vitamins B, C and E. Kohlrabi bulbs contain calcium, potassium, selenium, zinc and iron. The highest amount of beneficial substances - calcium, carotene and vitamin C - is found in young leaves, which can be easily added to salads and soups. Consuming kohlrabi supports bile production, which has a positive effect on digestion. Due to its fiber content, kohlrabi consumption is also suitable for dealing with constipation. Kohlrabi bulbs also contain biotin, which has a beneficial effect on skin and hair. Kohlrabi consumption is not recommended for people suffering from gastric mucosa inflammation or peptic ulcer disease, due to the content of irritating essential oils present in the bulbs.