How to grow Kohlrabi in Australia
Kohlrabi is a fast member of the cabbage family grown for its swollen, round stem, which sits just above the soil like a small green or purple ball. It is crisp, sweet and mild, eaten raw or cooked, and ready in as little as six to eight weeks. Grow it in the cool months and pick it young, before it turns woody.
📖 Our full guide: How to Grow Kohlrabi in Australia
At a glance
When to sow by region
| Region | When to sow | Regional note |
|---|---|---|
| South East Queensland | March to July | |
| Northern Rivers NSW | March to July | |
| Sydney & Coastal NSW | March to July | Cool-season preference; extended autumn-winter window. |
| Melbourne & Victoria | March to July | Sow Mar to Jul. Cool temps prevent bolting; Melbourne's long cool season ideal. |
| Adelaide & SA | March to July | |
| Perth & WA | March to August | Fast cool season brassica; sow Mar to Aug for autumn and winter bulbs. |
| Tasmania | September to February | Sow Sep to Feb. Fast brassica that never gets woody in cool summers. |
| Canberra & ACT | December to March | Sow Dec to Mar for quick autumn bulbs. Winter soil is too cold for germination in Canberra. |
| North Queensland | May to July | Dry season May to Jul. Kohlrabi is cool-season brassica; sow early dry season. |
| Darwin & Top End | May to July | Dry season May to Jul. Kohlrabi is cool-season brassica; sow early dry season. |
Where to plant
Grow kohlrabi in full sun in firm, fertile soil improved with compost, which holds moisture but drains well. Like other brassicas it does best in slightly limed soil and should not follow cabbages, broccoli or other brassicas in the same bed.
It grows fastest and sweetest in mild, cool weather. Hot, dry conditions make the bulbs woody and bitter, and cold snaps on very young plants can make them bolt instead of swelling.
- South East Queensland, the Northern Rivers, Sydney and Melbourne: sow from March to July.
- Adelaide: sow from March to July. Perth: sow from March to August for autumn and winter bulbs.
- Canberra: sow from December to March for quick autumn bulbs. Winter soil is too cold for germination.
- Hobart: sow from September to February. In cool Tasmanian summers it rarely gets woody.
- North Queensland and Darwin: sow in the early dry season, May to July.
Choosing a variety
Kohlrabi comes with green, white or purple skin; all have white or pale green flesh. Purple types tend to be hardier and slower, which suits later sowings into the cool season. Varieties described as slow to bolt are worth choosing for early sowings.
How to plant
- Sow seed thinly in drills about 1 to 1.5 cm deep, in rows 30 cm apart, or in cells for transplanting.
- Seed usually comes up in less than two weeks.
- Thin seedlings, or plant out cell-grown seedlings, to about 15 to 25 cm apart once they have their first true leaves.
- Protect seedlings from slugs and snails, and cover the bed with fine insect mesh against cabbage white butterflies.
- Sow small batches every few weeks for a steady supply.
Watering and feeding
Keep watering steady and even. Irregular watering makes the swollen stems woody and can split them. Mulch to keep the soil moist.
Feed for quick growth: compost before sowing and a liquid feed every couple of weeks while plants grow.
Harvesting
Harvest kohlrabi young, between golf-ball and tennis-ball size, when it is sweetest and crunchiest. Baby bulbs can be picked from about six weeks, and full-sized ones at about 8 to 12 weeks. Left too long, especially in hot, dry weather, they lose flavour and turn woody. Cut the stem just below the bulb.
Trim off the leaves, which can be cooked like cabbage greens, and keep the bulbs in a bag in the fridge for a week or two.
Growing in pots
Kohlrabi grows well in a pot at least 30 cm wide and deep, in sun or light shade, filled with quality potting mix. It is a good quick crop for containers. Water often and evenly.
Using it
Peel the tough outer skin, then slice or grate the bulb raw into salads and coleslaw, or roast, steam or stir-fry it. It tastes like a mild, sweet cross between cabbage and turnip.
Companion planting
Kohlrabi is quick and compact, so it fits between slower cool-season crops.
Good companions
- Beetroot A cool-season root crop that grows at the same pace and shares the bed without competing above ground.
- Onion A low, upright crop grown in the same season that fits between kohlrabi plants.
Keep apart
Avoid planting these close to kohlrabi.
- Strawberry Strawberries and brassicas are traditionally kept apart. The evidence is thin, but they need different beds and rotations.
- Tomato A summer crop with different needs, usually kept in a separate bed and rotation from brassicas.
Pests and diseases
Kohlrabi has the same pests as other brassicas. Insect mesh prevents most problems.
Pests to watch for
- Cabbage moth Holes in the leaves and green caterpillars underneath. Cover with fine mesh or squash caterpillars by hand.
- Aphids Grey clusters under the leaves. Hose them off.
- Slugs Seedlings eaten, with slime trails.
Diseases to watch for
- Clubroot Plants wilt on warm days and stay stunted; roots are swollen and distorted. Worst in acidic soil. Rotate brassicas and lime the soil.
Common questions
When is kohlrabi ready to harvest?
When the bulb is between golf-ball and tennis-ball size, usually 8 to 12 weeks after sowing, or from about six weeks for baby bulbs. Larger bulbs turn woody.
Why is my kohlrabi woody?
It was left too long, grew in hot, dry weather, or was watered unevenly. Pick young, grow it in the cool months and keep watering steady.
When should I plant kohlrabi?
From March to July in most regions, to August in Perth. Canberra sows from December to March, Hobart from September to February, and the tropics in the early dry season.
Can you eat kohlrabi leaves?
Yes. Young leaves can be cooked like cabbage or kale greens.
Why did my kohlrabi bolt?
Cold snaps on young plants, or heat and dry soil, can make kohlrabi flower instead of swelling. Sow at the right time for your region and keep the soil moist.
Can I grow kohlrabi in a pot?
Yes. Use a pot at least 30 cm wide and deep with quality potting mix, and water often and evenly.
Sources we checked: RHS: Kohl rabi, grow your own.