Kohlrabi is a quick, accommodating brassica whose edible swollen stem sits like a neat globe above the soil. Green and purple varieties both give mild, juicy crunch, and successive sowings make it a useful gap-filler between slower crops on beds or allotments.

When and how to sow

Sow little and often from March to August in module trays or directly where plants will grow. Use a sunny, reasonably firm bed enriched with garden compost, and protect early sowings with fleece if weather is cold. Thin or transplant to 20 cm apart in rows 30 cm apart. Choose a different area from last year's brassicas where club root has been troublesome.

Care

Keep soil moist throughout rapid growth, particularly in dry weather, to prevent woody stems and splitting. Weed while plants are small and apply a mulch once the ground has warmed. A light top-dressing of garden compost supports growth without overfeeding. Harvest promptly rather than waiting for oversized globes.

Common problems

Flea beetles pepper young leaves with tiny holes, especially during dry springs; fleece or fine netting offers useful protection. Club root causes swollen, failing roots, so rotate brassicas, improve drainage and avoid moving infected soil. Caterpillars and pigeons are also best excluded with securely fixed netting.

Harvest

Cut plants when the swollen stems range from golf-ball to tennis-ball size, while they remain sweet and tender. Larger kohlrabi soon becomes fibrous. Use a sharp knife or secateurs to cut at the base, then remove leaves, which can be cooked separately. Spring and autumn crops usually give the finest texture.

Growing Kohlrabi: frequently asked questions

When should I sow kohlrabi in the UK?

Sow little and often from March to August in module trays or directly where plants will grow.

What are common problems when growing kohlrabi?

Flea beetles pepper young leaves with tiny holes, especially during dry springs; fleece or fine netting offers useful protection.

When is kohlrabi ready to harvest?

Cut plants when the swollen stems range from golf-ball to tennis-ball size, while they remain sweet and tender.

General guidance for UK home gardens and allotments. Reference figures are typical values; your exact timing depends on your region, last-frost date and variety. Page updated 19 Sep 2026.