Knobby Kohlrabi Is Crisp, Juicy and Mild

Odd-looking though it is, kohlrabi is a good choice for your vegetable garden. The edible part—which is called a bulb, though it's technically a swollen stem—grows right on top of the soil. And it provides quite a show throughout the season, with its leaves (also edible) reaching out from the sides and top of the bulb like a spaceship designed by Dr. Seuss.

Kohlrabi has a cool name and an odd look, which makes it an outstanding choice for your garden. To get maximum impact from this cool-season vegetable, grow both colors: purple and pale green. And beyond its quirky good looks, kohlrabi is good to eat, of course. Peeled, sliced and eaten raw, it's crunchy and refreshing. You can also throw it on the grill, boil and puree it for soup, or cube it and cook it in a curry. Though it's a member of the cabbage family, its flavor is very mild; it's also a good source of vitamin C and potassium.

Common name: Kohlrabi

Botanical name: Brassica oleracea var. gongylodes

Plant type: Vegetable

Zones: Annual

Matures: 40 to 60 days; more for giant varieties

Height: About 12 inches

Family: Brassicaceae


Growing conditions
  • Sun: Full sun (but cool weather)
  • Soil: Well-drained, loose, rich
  • Moisture: Average to moist

Care

  • Mulch: To keep roots moist and the area weed-free
  • Pruning: None
  • Fertilizer: None

Propagation

  • Seed

Pests and diseases

  • Possible black leg, black rot, club root and fusarium wilt
  • Slugs, cabbage maggots, cabbage worms, cabbage loopers and cutworms

Garden notes

  • Sow seeds in the ground in April or May for an early summer crop. Plant again in late July or early August for a fall crop.
  • Harvest spring-sown kohlrabi when the bulbs are about 2 to 3 inches in diameter. Fall-grown kohlrabi stays tender even when it gets a little bigger. The giant cultivars, like Kossak, grow more than twice as large, up to 8 inches or more.
  • Prevent disease by rotating kohlrabi crops regularly; don't plant it in the same spot more than once every three or four years.

All in the family

  • Kohlrabi is a member of Brassicaceae family (previously known as Cruciferae), commonly called the cabbage or mustard family. Many other edibles are members of this family, including broccoli, Brussels sprouts, cabbage, cauliflower, kale, collards, mustard greens, radishes and turnips.
  • Several kohlrabi cultivars are available, including ‘Grand Duke', ‘Early White Vienna', ‘Kossak' (very large; matures at 8 inches in diameter) and ‘Kolibri' (a purple variety; see the top square photo).

Where to buy