Hardy - Transplants may be set out as soon as soil dries out in the spring. Established plants will tolerate frost into the lower 20's.
Acidity (pH) Tolerance
6.8 to 5.5 pH
Salinity (Ec) Tolerance
Biennial grown as an annual
Kohlrabi plants tend to be heavy feeders. Apply 1 to 2 pounds of an all-purpose fertilizer (20-20-20) per 100 feet of row. Side dress 3 weeks later with ammonium sulphate at a rate of 1/2 cup per 10 feet of row. Side dress kohlrabi again at time of first harvest to encourage side shoot development.
Kohlrabi should be supplied with sufficient water without waterloging the soil. Too much water is harmful.
Stress from inadequate water will decrease quality. Supplement sandy soils with organic matter to hold moisture.
Plant Development and Care
Kohlrabi is most often seeded directly into the garden but can be grown from transplants. Established plants will tolerate frost into the lower 20's.
They develop more quickly when they are protected with season extenders. Kohlrabi planted and harvested earlier typically develop fewer problems with insect pests and develops a tender, mild, sweet flavor.
As a cool season plant, Kohlrabi tends to bolt into flower in high heat, so it is best to plant early so it can mature in cool weather, or plant in mid-summer to allow cool conditions at harvest. Assuming a mid-October average date of first frost, a fall crop may be transplanted between July 1st and August 15th for fall harvest. Kohlrabi may be directly seeded July 5th to 10th for fall harvest.
Germination Time (Days)
20 days at 50° F 10 days at 59° F 6 days at 68° F 5 days at 77° to 95° F