Growing Kohlrabi: The Forgotten Vegetable

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Growing kohlrabi means growing a crisp, crunchy and cruciferous garden treat.
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Kohlrabi likes rich soil, cool weather, plenty of water and proper spacing, and it’s one of the few vegetables that will tolerate light shade.

K is for kohlrabi – a sister to the cabbage. Growing kohlrabi means growing a crisp, crunchy and cruciferous garden treat. This vegetable’s shape resembles the original Russian Sputnik, an early spacecraft. No wonder Edward C. Smith, in his Vegetable Gardener’s Bible, says, “Kohlrabi’s unique growth habit makes the garden look like a moon landing site.” Sometimes called an aboveground turnip, kohlrabi’s stem, rather than the root, is swollen, and the leaves attach directly to the top of the bulbous stem like spokes. Gardeners unfamiliar with this vegetable often wonder which end is up and which end to eat.

This curious member of the Brassica genus and the Brassicaceae (or Cruciferae) family dates back to 1554 in Italy, according to edible plant historian E. Lewis Sturtevant. Its name is a combination of the German words for cabbage and turnip. Despite its long history, kohlrabi has never quite caught on in the United States. On the other hand, northern Europeans have long appreciated this vegetable. Kohlrabi is popular in Japan, China and Southeast Asia.

Variations on a theme

Kohlrabi is pretty in purple, but most kohlrabi grown in the United States is green with a white interior. Renee Shepherd, owner of Renee’s Garden Seeds in Felton, California, sells purple Kolibri and green Kongo varieties as a “Crispy Colors Duo” mix. She plants both in a mosaic pattern in her garden and stands back to enjoy visitors’ reactions. She believes kohlrabi is ideal for children’s gardens because of its unique flying saucer shape, its great color pattern, and its wonderful taste when peeled and eaten fresh. “It’s fun to interplant a bed of green kohlrabi with a purple variety laid out in the shape of a child’s first name,” Shepherd says.

Last summer we grew Kossak, a variety that reached a large size without getting woody. According to Steve Bellavia, vegetable researcher at Johnny’s Seeds in Winslow, Maine, Kossack was bred for storage. Bellavia put several bulbs of Kossack on a shelf in his root cellar this fall. “They’ll last a long time if you have cool, high-humidity conditions,” he says. “I have an old dirt floor in my cellar so the temperatures are cool and the humidity is high. In the refrigerator they would be fine, too.”

Iowa gardener and garden photographer David Cavagnaro also stores kohlrabi in a root cellar, in shallow trays of soil.

Bellavia favors Winner, a midseason variety that is ready for harvest in 45 days and holds well in the field without splitting, for fresh eating. “Eder will grow faster, and Korridor has organic seeds, but Winner tastes better,” he says.

Josh Kirschenbaum, a horticulturist at Territorial Seeds in Cottage Grove, Oregon, thinks of kohlrabi as “one of the most unappreciated vegetables out there,” though he loves it. He says his favorite variety is Superschemltz, a Swiss introduction that produces juicy, 8- to 10-inch bulbs and an extra-large root system that seeks out water.

Territorial Seeds owner Tom Johns once said of Superschmeltz, “It’s so big you almost have to take an ax to it!” In their winter trials, Superschmeltz also tended to withstand the harsh temperatures the best.

Growing kohlrabi

Kohlrabi likes rich soil, cool weather, plenty of water and proper spacing, and it’s one of the few vegetables that will tolerate light shade. Since it is a heavy feeder, Shepherd works plenty of well-aged manure or compost into the bed before planting kohlrabi, and she feeds every three weeks or so with a balanced liquid fertilizer, compost tea or fish emulsion and kelp solution.

An ideal candidate for northern climates, this vegetable grows best at temperatures between 65 and 77 degrees Fahrenheit. Both Kirschenbaum and Shepherd start their kohlrabi indoors five to six weeks before the last frost date. “I find that healthy, sturdy transplants are better able to survive lurking slugs or snails and unexpected inclement weather,” says Shepherd. Kirschenbaum says that direct-seeded kohlrabi can bolt when subjected to significant temperatures and moisture fluctuations.

Space kohlrabi seedlings 6 to 8 inches apart when you set them into the garden. Crowded kohlrabi will not develop the distinctive swollen stem. The plants grow quickly, with some varieties ready to harvest in 38 to 40 days. For the best taste, pick kohlrabi, except for large varieties like Kossak and Superschmeltz, when they are the size of a tennis ball.

Southern gardeners should consider growing kohlrabi as a fall crop, Bellavia suggests. Plant the seedlings in late summer and leave them in the ground until November or December. He believes the quality is higher because the plants have consistently cool temperatures but not too much freezing. Fall is Kirschenbaum’s favorite time to plant kohlrabi “because the flavor gets so much sweeter after a few frosts.”

Pest management made easy

Like its cabbage-family siblings, kohlrabi is susceptible to pests like cabbage worms, root maggots and flea beetles. We protect our kohlrabi seedlings from root maggots with row covers until they’re large enough to fend for themselves, and we sometimes spray with Bt (Bacillus thuringiensis) to control cabbage worms. Kirschenbaum emphasizes the importance of early control for flea beetles and recommends either an insecticidal soap or a pyrethrum. Territorial Seeds sells a cabbage collar, a paper ring embedded with a copper product to keep moths from laying their eggs at the base of the plants, and Shepherd uses non-toxic Sluggo to combat slugs and snails.

Nutritional value of kohlrabi

Nutritionally, kohlrabi bulbs and leaves are great sources of vitamins A and C, calcium, potassium and fiber, and they are low in calories, with about 40 calories per cup. And, like all cole crops, kohlrabi is packed with powerful anti-cancer capabilities.

Culinary kohlrabi

Most kohlrabi aficionados are from Eastern Europe, where this vegetable is generally cubed and cooked in soups or stews, mashed along with potatoes and carrots, or creamed or sautéed. Delicious raw as a snack, kohlrabi tastes like a cross between a cabbage and an apple. Shepherd prefers her kohlrabi raw with hummus or a dip, but she sometimes serves it cooked in a rich cream sauce and sprinkled with grated nutmeg or stir-fried with carrot slices and scallions and seasoned with fresh gingerroot. These two great kohlrabi recipes by Renee Shepherd will get you started:

Kohlrabi Stir Fry Recipe
Pickled Kohlrabi Recipe

Quick and easy to grow, nutritious, delicious and curious, too, kohlrabi deserves space in your vegetable garden.  

Margaret Haapoja fills her home garden in Bovey, Minnesota, with kohlrabi and other delicious vegetables.

Kohlrabi varieties and sources

‘Kolibri’: (Purple)
Johnny’s Selected Seeds

Renee’s Garden

Territorial Seed Co.

J.W. Jung Seed Co.

• Territorial Seed Co.

• Jung Seed Co.

• Renee’s Garden

‘Kossack’: (Large)
• Johnny’s Selected Seeds

• Territorial Seed Co.

• Jung Seed Co.

‘Superschmeltz’: (Large, heirloom)
• Territorial Seed Co.

• Johnny’s Selected Seeds

Stokes Seeds