Kohlrabi

Growing Conditions

Kohlrabi prefers cool temperatures between 60°F and 70°F. It tolerates light frost and can be sown earlier in spring than most crops. Heat causes the stem base to become fibrous and woody before reaching full size. Full sun is preferred.

Cold climates: Direct sow 4–6 weeks before last frost for spring, and again 8 weeks before first frost for fall.

Warm climates: Grow as a fall and early spring crop. Fast maturity makes it easier to fit into a warm-climate cool season than slower brassicas.

Sowing & Planting

Direct sow ¼ inch deep, 3 inches apart. Thin to 6 inches when seedlings are 2 inches tall. Kohlrabi can also be transplanted — start indoors 3–4 weeks before setting out. It does well direct sown.

Care & Maintenance

Consistent moisture produces the best texture. Dry conditions followed by heavy rain causes cracking. Kohlrabi is a light to moderate feeder — amend with compost at planting, no additional fertilizing needed in healthy soil.

Common Problems

Woody texture results from leaving the stem base in the ground too long or from heat stress during development. Harvest promptly at 2–3 inches. Flea beetles leave small holes in leaves — mostly cosmetic damage. Cabbage worms are occasional but less common on kohlrabi than on heading brassicas.

Harvest

Harvest when the swollen stem base is 2–3 inches in diameter. At this size the texture is crisp and the flavor mild and slightly sweet. Kohlrabi left to grow beyond 3–4 inches becomes increasingly fibrous. The leaves are edible — use them like kale or collard greens.

Varieties

Green kohlrabi (Early White Vienna, Kolibri) is the standard type. Purple kohlrabi varieties have a more dramatic appearance but identical flavor. Giant kohlrabi varieties (Superschmelz) can grow to 8–10 inches without becoming woody — these are worth growing if you want to let them size up. All types are grown identically.