How to grow kohlrabi

Brassica oleracea (Gongylodes) · Brassicaceae · Vegetable

Kohlrabi is a cool-season vegetable in the Brassicaceae family, grown either from a direct sowing or from transplants. It wants full sun, though it tolerates a little afternoon shade in hot regions and steady, even moisture. From sowing to first pick is about 45–60 days. It handles frost well and a light freeze often improves the flavour.

Grower’s note: Harvest the swollen stem at 2-3 in across - bigger bulbs turn woody. Fast enough to succession sow every couple of weeks in spring and again for fall.

Sowing

Sow about 0.5″ deep, into soil between 45–85°F — germination is quickest near 70°F. It comes up fast (5–10 days). For an early crop, start seed indoors about 5 weeks before your last spring frost and grow it under bright light.

Spacing & layout

Give each plant about 6″ along the row with roughly 12″ between rows. On a square-foot grid that is 4 per square foot. Allow at least 12″ of loose, workable soil for the roots. It grows well in containers at least 10″ deep.

Fitting it to your season

As a cool-season crop, kohlrabi does its best growing in the mild weather of spring and fall and tends to bolt or turn bitter in summer heat. A second sowing in late summer, timed to mature as the weather cools, is usually the better crop of the year — and light frost only sweetens it.

Quick facts

When to plant kohlrabi

Companions

Common problems

Pests: cabbage worm, flea beetle, cabbage root maggot, aphids.

Diseases & disorders: clubroot, black rot.

Same family (Brassicaceae)

Rotate these so they don’t follow each other in the same bed year to year.

Figures are typical home-garden ranges from Cooperative Extension planting guides, cross-checked against multiple state sources. Your variety and conditions will vary.