Kathryn Fontenot, Koske, Thomas J. | 4/1/2005 1:18:03 AM
Kohlrabi is a delicious, old-European member of the cabbage family that grows well in Louisiana's cool seasons. It has been described as an above-ground turnip. It has a sweet, crisp, mild, turnip-like flavor unless left to mature too long or if grown in too-hot of a season. The name comes from the German words for cabbage and turnip.
The part you eat is a swollen stem. It looks like a baseball-sized turnip with leaves sticking out like spokes from a wheel. You eat the swollen stems raw or prepare them in a turnip-like dish. The young, tender leaves also may be harvested and eaten as a turnip green.
Kohlrabi can be seeded in Louisiana throughout the cool season, but it is best planted in the late winter and mid fall. Transplants may be started from seed 5 to 6 weeks before setting out. It will be ready for harvest in about 2 to 2 1/2 months from the seeding date.
The plant will grow well in average to rich soils. Fertilize as you would for turnip and other root crops. Before planting, apply 6 to 7 pounds of a 13-13-13 fertilizer or equivalent per 100 feet of row. One pound is approximately a pint or 2 cups. Plant the seeds only about ¼ inch deep and thin emerging plants to about 6 to 8 inches apart in the row. Rows can be spaced 18 inches apart.
A constant, rapid growth produces the best quality kohlrabi. To get this type of growth, provide an even supply of moisture and sidedress the plants about every 3-4 weeks with about 1.5 pounds calcium nitrate per 100 feet of row.
Uneven or slow development can result in growth cracks and a tough, fibrous outer skin. If the stem does become tough, trim the outer layers of skin because a tender inside may still be salvaged. Kohlrabi is harvested when the stems are about 3 inches in diameter, depending on the growth rate. Older and larger stems may be more fibrous and stronger flavored.
The most commonly planted open pollinated cultivars are the Early White Vienna and Early Purple Vienna. The hybrid Grand Duke is an All-American selection and has reliably produced a high-quality stem. The hybrid Winner is an improved Grand Duke type. Another new hybrid worth trying is Rapid Star.
Cool-season pests of kohlrabi and other cabbages are cabbage worms and aphids. Use a Bacillus bacteria (B.t.) spray to control worms. Malathion will control the aphids or an insecticidal soap may also be used. Observe the 7-day preharvest interval for Malathion as well as re-entry interval as posted on the labels.