Growing Hints for Kohlrabi

Kohlrabi is an odd but easy to grow member of the cabbage family. Unlike other brassicas, it is not the leaves or flower buds that are eaten, but the swollen stem that is shaped something like a turnip.

Kohlrabi seed germinates quickly and is fast growing, so it is usually planted directly in the garden rather than started indoors and transplanted. The plants can be grown more closely than most other brassicas. Like cabbage, kohlrabi is a heavy feeder that grows best in fertile soil that is neutral rather than acidic. Working some compost and lime into the bed before planting will speed the growth of kohlrabi, and it is the plants that have grown quickly and steadily that are most tender and have the best flavor.

Like other brassicas, kohlrabi grows best in cool weather. It matures quickly enough that both a spring and a fall crop are easily grown. A late summer planting, maturing in the cool days of autumn, may be the best tasting, but a special effort must be made to keep the seed cool and moist while germinating if the weather is hot and dry when it is planted.

It is important to thin kohlrabi plants to at least four inches apart, and weeds must be controlled if the stems are to reach a reasonable size. Kohlrabi roots are rather shallow, so use care when cultivating. Once the plants are a few inches high, a mulch can be spread around the plants to control weeds and to keep the soil cool and moist, but be sure that you don't cover the stems.

Kohlrabi can sometimes be bothered by cabbage worms or flea beetles. Since the leaves of kohlrabi are generally discarded, a minor infestation that does only slight damage to the leaves can generally be ignored. Treat more threatening pest outbreaks with BT (for caterpillars) or floating row covers (for all insect pests). Avoid planting kohlrabi where any other cabbage family crops have grown in the past two or three years to prevent the appearance of disease.

Anyone who has faced tiny cabbage worms hidden in the tiny crevices of broccoli tops will appreciate the simplicity of harvest and preparation of kohlrabi, since the swollen stem forms a solid mass that no insects can hide in. When the plants are ready for harvest, simply use a serrated knife to cut the plant off at ground level.

Kohlrabi should not be peeled, as the skin is generally considered to be the most flavorful part of the plant. Kohlrabi can be sliced and eaten raw, added to salads or used in cooking. It is a popular addition to soups and stews for those who are familiar with it.

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