Common names: kohlrabi, turnip-rooted cabbage, stem turnip, turnip cabbage
Botanical name: Brassica caulorapa
Origin: horticultural hybrid
Varieties
Early White Vienna (55 days); Early Purple Vienna (60 days).
Description
Kohlrabi is a hardy biennial grown as an annual and is a member of the cabbage clan. It has a swollen stem that makes it look like a turnip growing on a cabbage root. This swollen stem can be white, purple, or green, and is topped with a rosette of blue-green leaves. In German, kohl means cabbage and rabi means turnip—a clue to the taste and texture of kohlrabi, although it is mild and sweeter than either of them. Kohlrabi is a fairly recent addition to the vegetables grown in northern Europe. In this country, nobody paid it any attention until 1800,
Where and when to grow
All cole crops are hardy and can tolerate low 20°F temperatures. Kohlrabi tolerates heat better than other members of the cabbage family, but planting should be timed for harvesting during cool weather. Kohlrabi has a shorter growing season than cabbage. It grows best in cool weather and produces better with a 10° to 15°F difference between day and night temperatures. If your area has cold winters, plant for summer to early fall harvest. In the South, plant for harvest in late fall or winter. With spring plantings, start kohlrabi early so that most growth will occur before the weather gets too hot.
How to plant
Kohlrabi likes fertile, well-drained soil with a pH within the 6.5 to 7.5 range; this discourages disease and lets the plant make the most of the nutrients in the soil. The soil should be high in organic matter. When you’re preparing the soil for planting, work in a complete, well-balanced fertilizer at the rate of one pound per 100 square feet or 10 pounds per 1,000 square feet. Cole crops are generally grown from transplants except where there’s a long cool period. Kohlrabi, however, can be grown directly from seed in the garden. Sow seeds in rows 18 to 24 inches apart and cover them with a quarter to a half inch of soil. When the seedlings are growing well, thin them to five or six inches apart—you can transplant the thinnings. Cultivate carefully to avoid harming the shallow roots.
Fertilizing and watering
Fertilize before planting and again at midseason, at the same rate as the rest of the garden. Detailed information on fertilizing is given in “Spadework: The Essential Soil” in Part 1. Kohlrabi should have even moisture or it will become woody.
Pests
The cabbage family’s traditional enemies are cutworms and caterpillars. Cutworms, cabbage loopers, and imported cabbage worms can all be controlled by spraying with bacillus thuringiensis, an organic product also known as Dipel or Thungicide. Detailed information on pest control is given in “Keeping Your Garden Healthy” in Parti.
Diseases
Cabbage family crops are susceptible to yellows, clubroot, and downy mildew. Lessen the incidence of disease by planting disease-resistant varieties when they’re available; maintaining the general health of your garden; and avoiding handling the plants when they’re wet. If a plant does become infected, remove and destroy it so it cannot spread disease to healthy plants. Detailed information on disease prevention is given in “Keeping Your Garden Healthy” in Part 1.
Storing and preserving
Kohlrabi will store for one week in a refrigerator or for one to two months in a cold, moist place. Kohlrabi can also be frozen. Detailed information on storing and preserving is given in Part 3.
Serving suggestions
Small, tender kohlrabi are delicious steamed, without peeling. As they mature you can peel off the outer skin, dice them, and boil them in a little water. Kohlrabi can also be stuffed, like squash-
Try young kohlrabi raw, chilled, and sliced; the flavor is mild and sweet, and the vegetable has a nice, crisp texture. You can also cook kohlrabi, then cut it into strips and marinate the strips in an oil and vinegar dressing; chill this salad to serve with cold cuts. Cooked kohlrabi can be served just with seasoning and a little melted butter or mashed with butter and cream. For a slightly different flavor, cook it in bouillon instead of water.
