A Unique and Surprisingly Tasty Crop
Subspecies: Brassica oleracea var. gongylodes
Kohlrabi is a cole crop, like cabbage, and has a flavor similar to turnips and rutabagas. Kohlrabi does well on its own and as a companion plant mixed in with other crops. It is suitable for vegetable gardening and for landscape arrangements. Growing kohlrabi is an interesting, edible addition to ornamental plantings.
Recorded mentions of Kohlrabi being grown as a vegetable go back as far as Ancient Rome. It is no longer widely grown in the United States, but should be considered for the small garden as it does not require much space and has a sweeter taste than its cabbage family relatives. Read on for our full guide on how to grow kohlrabi yourself.
Kohlrabi performs better in cool temperatures, but it can be cultivated throughout the season in zones 6 and farther north. While Kohlrabi does better in cooler weather, it does not tolerate cold well. If exposed to temperatures below 32°, the plants will bolt. Extended temperatures lower than 50° can also cause the plants to bolt.
Kohlrabi seeds need to be planted directly in the ground. Soil needs to be around 45° – 85°F for adequate germination.
Plant the seeds about 1 month before last frost. Seeds should be planted at a depth of ½ inch. There should be 1 inch between seeds and 12 inches between rows.
Seeds should be started inside in areas with shorter seasons. Place transplants in the soil 2 – 3 weeks after last frost.
Kohlrabi needs to be harvested before summer temperatures are consistently above 80°F.
Fall harvests are possible if seeds are planted in late summer when temperatures begin their downward trend.
Purple kohlrabi and white kohlrabi are the two predominant types grown in the home garden.
Early Purple Vienna is a variety with small, purple bulbs known for their tenderness. It is best for spring planting. This variety is most commonly used for Hungarian cuisine.
Grand Duke is a variety with white bulbs. It is suitable for spring and fall planting. It is often used in soups and stews.
If Cabbage Root Maggots are present the plants will show wilting and may eventually die. Plants should be cleaned and transplanted.
Remove Cabbage worms manually and destroy them. Using row covers made of netting or tightly woven cheesecloth will help protect the plants from Cabbage worm damage. Row covers need to be removed from the plant rows once summer temperatures are consistently above 78°F.
In addition to row covers, diatomaceous earth can be used to control flea beetles.
Cardboard collars installed around individual plants will prevent most cutworms.
Kohlrabi needs to be harvest when stems reach a diameter of 3 inches. If kohlrabi is left in the ground past this stage it will become fibrous and tough. Kohlrabi will keep well in the refrigerator or in a root cellar, provided the leaves are removed and the space has low humidity.