Knol-kohl Brassica oleracea (Gongylodes Group)

The Gongylodes Group is commonly called kohlrabi. The genus name Brassica is Latin for cabbage. It is a low, stout cultivar of cabbage.  The plants will bear white, green or purple, turnip-like edible swollen stems. For the best crop, it should be grown in the cooler temperatures of spring and fall.  Plants will not produce well when daytime temperatures remain above 80 degrees.  

Having a shallow root system, this plant can benefit from mulch being applied.  Mulching will also assist in keeping weeds at bay.

Kohlrabi is best harvested when the fat, rounded vegetable is 2-3" across.  Harvesting at that time will produce the most tender and sweet vegetable.  If harvested when the plant is larger in size, it will tend to become tough.  As well as boiling, steaming or baking, its leafy tops can also be harvested and eaten raw in salads or slaws.

Although not common, red varieties are also available.

Insects, Diseases and Other Plant Problems:  Possible disease problems with kohlrabi are downy mildew and bacterial rot.  Insects affecting the plants include aphids, cabbage loopers, cutworms, flea beetles and cabbage worms.

The Clemson Cooperative Extension Home and Garden Information Center has a factsheet on common Cole crop diseases and other plant problems.

VIDEO Created by Elisabeth Meyer for "Edibles, Bulbs, and Houseplants" a plant identification course offered in partnership with Longwood Gardens.   

More information on Brassica oleracea.