Knol-kohl Brassica oleracea (Kohlrabi Group)

This group of hybrids contains kohlrabi. It is a biennial cultivar of the wild cabbage and was hybridized in Europe sometime before the 1500s. The genus name Brassica is Latin for cabbage.

This low-growing plant will only grow 6 inches to 1 foot tall. They do best in full sun and in any amended garden soil. They can be directly sown in the garden or purchased as seedlings and planted in either spring or fall. Provide adequate nitrogen for best results. Get a soil test before planting and fertilize according to the results. Apply mulch for moisture retention as they have shallow roots. In NC plant 1–2 weeks before the last frost, or in mid to late summer for a fall or early winter harvest. They can tolerate frost but not a hard freeze.

Kohlrabi is the swollen part of the stem that sits just above the ground. From it grows a few scattered stems with leaves. It is best harvested when the rounded area is 2-3" across as this will produce the most tender and sweet vegetable. If left too long they will become tough and woody.  Eat kohlrabi raw or cooked. If left in the ground for the second year it will bloom and set seeds.

Use kohlrabi in the edible garden, border or mass planted.

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. See pests of crucifers to the left.

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

More information on Brassica oleracea

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.