Kohlrabi is a cool season biennial in the Brassicaceae family, sharing species name Brassica oleracea with cauliflower, cabbage, collards, kale, brussels sprouts, and broccoli. Kohlrabi is a little known, yet delightful vegetable with mild flavor and the texture of a juicy, sweet radish. The edible portion of kohlrabi is not the root, but rather the round, swollen stem of the plant. Leaves are also edible. Kohlrabi varies in color from light green to purple.

Soil Nutrients and Requirements

Requires well drained soil with pH 6.0-7.5. A general guideline is 2-3 lbs of 8-16-16 fertilizer over 100 sq ft of garden area two weeks before planting. If boron is not present in your soils, consider adding 1 Tbs per 100 sq ft.

Seeding Depth

Seed depth: 1/4-1/2″

Plant Spacing

Plant spacing: 4″

Row Spacing

Row spacing: 12-18″

When to Sow

Start transplants 4-6 weeks before planting date, or direct seed as soon as ground can be worked in early spring or late summer. Germinates from 45-85 degrees. Best quality is for fall harvest.

Harvest

Harvest when stem swells to 3-5″ and is easily visible above the soil. Larger plants become woody.

Storage

With leaves removed, kohlrabi can be stored in the fridge for several weeks.

Pest Info

• Insect pests, including cabbage looper, imported cabbage worm, and diamondback moth, are largely of the Lepidoptera order and can thus be controlled by Bacillus thuringiensis (such as Dipel DF, see Supplies) and/or spinosad (such as Entrust™), preferentially in rotation with one another to prevent selection of resistant individuals (check with your certifier before applying).
• Protect plants from flea beetles by using floating row covers in the early season. Root maggots can be controlled by applying beneficial nematodes.

Disease Info

Black Rot, caused by the bacterium Xanthomonas campestris and Club root, caused by the soil borne fungus Plasmodiophora. Prevention includes resistant varieties, crop rotation, removal or tillage of plant debris, eliminating cruciferous weeds, and handling plants in dry conditions.