How to Grow Kohlrabi
Brassica oleracea (Gongylodes group)
An alien-looking brassica with a crisp, sweet, broccoli-meets-apple bulb.
By the Plants by Zone Editorial Team · Reviewed June 1, 2026
About kohlrabi
Kohlrabi is an unusual, easygoing brassica grown for the swollen stem that forms just above the soil — crisp, mild, and sweet when young. It matures fast and shrugs off light frost, making it a great cool-season crop for spring and fall. Pick it small for the best texture.
When to plant and harvest kohlrabi
Timing is relative to your frost dates. Find your USDA zone for exact dates, or browse the month-by-month calendars.
Start seeds indoors
4–6 weeks before last frost (optional)
Transplant outdoors
2–3 weeks before last frost
Direct sow
2–4 weeks before last frost, and again in late summer
Harvest
Spring and fall
How to grow kohlrabi step by step
- 1
Direct sow or transplant into rich soil while the weather is still cool.
- 2
Thin or space to about 6 in apart so bulbs have room to swell.
- 3
Keep moisture even and steady — uneven water makes bulbs woody and split.
- 4
Feed lightly for fast, tender growth.
- 5
Harvest when bulbs are 2–3 in across, before they turn fibrous.
- 6
Sow again in late summer for a frost-sweetened fall crop.
Common problems growing kohlrabi
⚠ Woody, fibrous bulbs
Caused by heat, age, or dry spells — grow in cool weather, water evenly, and harvest young at 2–3 in.
⚠ Cabbage worms on leaves
Cover with insect netting or use Bt; the bulb itself usually escapes damage.
⚠ Bulbs fail to form
Too crowded or too hot — give proper spacing and grow in the cool shoulder seasons.
✗ Keep away from
🧺 Harvesting kohlrabi
Cut the bulb at the base once it reaches 2 to 3 inches across — golf-ball to tennis-ball size — when it’s crisp and sweet. Larger bulbs turn woody, so don’t wait; the leaves are edible too, cooked like kale.
Kohlrabi: frequently asked questions
When do I harvest kohlrabi?＋
Pick the bulbs young, at 2–3 inches across. Left too long they turn tough and woody, so harvest promptly once they reach size.
Do you eat the bulb or the leaves?＋
Both — the swollen stem is the main crop, crisp and mild, and the leaves can be cooked like any hardy green.
Grow kohlrabi in your zone
See exactly when to plant and what else to grow alongside kohlrabi, tailored to your USDA hardiness zone.
