Culture
Easily grown in organically rich, consistently moist, well-drained loams in full sun. Soil pH should be between 6 and 7. Kohlrabi is typically grown in the cool temperatures of spring or fall. It needs cool temperatures to produce the best crop. Plants generally grow poorly when daytime temperatures consistently exceed 80 degrees F. For spring planting, sow seed indoors 6-8 weeks before the last spring frost date or sow seed outdoors in the garden about 2 weeks prior to the last frost date. In the alternative, transplants may be purchased from local nurseries for planting outdoors two weeks prior to last spring frost date. Set plants in the ground about 4-6" apart in rows that are 18" apart. For fall harvest, sow seed indoors around July 1 and then plant the seedling in the garden in mid-August. Keep plants consistently moist. Apply mulch around plants to protect the shallow roots, reduce weeds and retain soil moisture. Kohlrabi may be picked after the bulbs reach 2-3" across. Rotate crops to avoid soil borne diseases.
Noteworthy Characteristics
Brassica oleracea (Gongylodes Group), commonly called kohlrabi is a cool weather vegetable that produces fat, rounded, turnip-like enlargements of the stem just above the soil surface. Kohlrabi is best picked when it reaches 2-3" across (tender and sweet when small). It usually becomes tough and woody if allowed to grow beyond 3" across. Leafy tops (taste reminiscent of turnip greens) may also be harvested. Plants will typically grow to 12" tall and as wide. Kohlrabi may be eaten raw (add to salads, vegetable platters or slaw) or cooked (steam, bake or boil). Kohlrabi belongs to the Brassica family which includes other cool season vegetables such as kale, Brussels sprouts, broccoli, cauliflower and cabbage.
Genus name comes from the classical Latin name for cabbage.
Specific epithet means of vegetable gardens.
Common name comes from the German words kohl meaning cabbage and rabi meaning turnip.
Problems
Potential insect problems include aphids, cabbage loopers, cabbageworms, cutworms and flea beetles. Potential disease problems include downy mildew and bacterial/soft rot.