How to Grow Kohlrabi

Kohlrabi is an unusual brassica that forms a swollen, bulb-like stem (technically not a root, but a swollen stem base) just above the soil line. This edible 'bulb' has a crisp, juicy texture with a flavor like a milder, sweeter broccoli stem. It's excellent raw in slaws and salads, roasted, or braised. Despite its exotic appearance, kohlrabi is among the easier brassicas to grow and is ready in just 45–60 days from transplant.

Kohlrabi thrives in the same cool conditions preferred by broccoli, cabbage, and kale, making it an excellent choice for spring and fall planting. It tolerates frost and grows quickly, making it a productive gap-filler between other crops. Two color types are common: pale green (slightly milder) and purple (slightly sweeter, with identical pale interior flesh). Both types are harvested at the same stage and have similar growing requirements.

Growing Tips

Harvest kohlrabi when bulbs are 3 inches in diameter — this is the ideal size for the best texture and flavor. Larger bulbs (over 4 inches) become woody and fibrous with a less pleasant texture, though some varieties (like 'Gigante') are bred to stay tender at larger sizes.
The leaves are edible — treat them like kale or collard greens. Cook in stir-fries, soups, or sauté with garlic. Don't waste the greens; they're nutritious and flavorful, especially from young plants.
Kohlrabi is an excellent crop for interplanting with slower-maturing crops like tomatoes, peppers, and winter squash. Start it in the same bed in early spring — kohlrabi will be harvested by the time warm-season crops need the space.
Purple kohlrabi varieties are often more heat-tolerant and stay tender at larger sizes than green varieties, making them a better choice for warmer climates and later planting dates where some heat may be encountered.
For raw eating, peel kohlrabi (the skin is tough), then slice thinly or julienne for slaws. A simple preparation of matchstick kohlrabi with lemon juice, salt, and fresh dill showcases its fresh, mild flavor beautifully.

Companion Planting

Kohlrabi's compact size makes it an efficient interplanting option in gaps between larger brassica transplants — sow seeds in the spaces between broccoli or cabbage transplants for productive use of early-season space. Rotate with all other brassicas on a 3-year cycle. The planner helps you time these dense multi-crop plantings.

FAQ

When should I plant kohlrabi?

Transplant kohlrabi 2–4 weeks before your last spring frost for a late spring harvest, or plant from seed in midsummer (6–8 weeks before first fall frost) for a fall harvest. Kohlrabi is a fast-maturing cool-season crop — at 45–60 days from transplant, it fits into gaps in spring and fall planting schedules that larger brassicas can't fill.

What is kohlrabi and what does it taste like?

Kohlrabi is a brassica (same family as broccoli and cabbage) that forms a swollen, bulb-like stem above the soil. The flesh is crisp, juicy, and mild — often described as a cross between broccoli stems and apple, with a mild, slightly sweet flavor. Young kohlrabi is excellent raw; larger bulbs are better cooked. Both the bulb and the leaves are edible.

Why is my kohlrabi woody and tough?

Woody kohlrabi results from harvesting too late (bulbs over 3–4 inches diameter become fibrous), drought stress during growth, or high heat during development. Harvest at 3 inches for the best texture. Maintain consistent moisture throughout the growing period. If woody bulbs are a recurrent problem, try varieties like 'Winner' or 'Gigante' which maintain tenderness at larger sizes.

Can kohlrabi survive frost?

Yes — kohlrabi tolerates frost down to 25–28°F once established, making it suitable for early spring and late fall planting. It can be protected through light frosts with row cover and may continue growing into November or even December in mild zones. Frost exposure slightly improves flavor by triggering sugar conversion, similar to other brassicas.

How do I use kohlrabi?

Peel the tough outer skin first, then enjoy kohlrabi raw or cooked. Raw: slice thin for chip-like snacking, julienne for coleslaw, or grate into salads. Cooked: roast cubed kohlrabi with olive oil at 400°F until caramelized, add to stir-fries, or braise in broth. The leaves can be sautéed with garlic like kale. Kohlrabi pairs well with apples, mustard, lemon, dill, and caraway flavors.