When to Plant Kohlrabi in Cairns, Tropical Guide

Sow March to August. Right now in September it is out of season. The next sowing month is March.

Published · Last reviewed · By Garden Buddy
Growing advice is reviewed by hand. Planting dates, current conditions and prices on this page update daily.

This Kohlrabi guide is written for the Tropical zone, which takes in Cairns, Townsville and Darwin. Somewhere else? Your postcode picks the right one.

Not your zone? Brisbane Sydney Melbourne Canberra Alice Springs Perth

Also handy: will it frost this week? and what grows in shade.

Kohlrabi

Photo: Wikimedia Commons

Kohlrabi is technically not a root vegetable. The edible part is a swollen stem that forms above ground. Fast-growing (55-70 days), mild-flavoured, and versatile in the kitchen, kohlrabi is an underused gem in Australian gardens. It thrives in cool weather, handles light frost, and is one of the best brassicas for beginners. Both the bulb and leaves are edible.

Planting Calendar for Tropical

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
- - S S/T/D S/T/D S/T/D T/D T - - - -

S = Seed Tray   T = Transplant   D = Direct Sow

Want a nudge when it is Kohlrabi sowing time in Cairns?

One email a week with what is worth planting in the Tropical zone right now, Kohlrabi included, plus which veg has jumped in price at the supermarket. Free, and you can stop it in one click.

Current Growing Conditions

Soil temperature: 21.4°C (optimal range: 10–30°C) ✓ Ready to plant

Modelled from Open-Meteo forecast (Cairns), not a live sensor.

How to Grow Kohlrabi in Tropical Australia

When to Plant

March to July (dry season only). Kohlrabi bolts quickly in hot, humid conditions. Plant at the start of the dry season for best results.

Soil
Rich, well-drained soil with plenty of organic matter. Prefers neutral to slightly alkaline soil. Dig in compost and well-rotted manure before planting. Add lime to acidic soils (critical for preventing clubroot).
pH Range
6.5-7.5
Sunlight
Full sun (6+ hours). Tolerates light shade, especially in warmer zones where afternoon shade prevents bolting.
Spacing
20cm apart, 35cm between rows
Watering
Consistent, even moisture throughout growth. Water deeply 2-3 times per week. Inconsistent watering causes the stem bulb to become woody and split. Drip irrigation preferred.

Companion plants: Beetroot, Celery, Cucumber, Dill, Lettuce, Onion

Avoid planting near: Strawberry, Tomato, Runner Bean

Tropical Growing Tips for Kohlrabi

Recommended Varieties

  • White Vienna
  • Purple Vienna

Key Challenges

  • Rapid bolting in heat
  • Caterpillar pressure year-round
  • Clubroot in acidic tropical soils

Pro Tips

  • Grow fast, kohlrabi matures in 55-70 days which fits the dry season
  • Net against caterpillars from day one
  • Harvest at tennis ball size. Do not let them get too large in warm conditions or they become woody

Harvesting Kohlrabi

When ready: Stem bulb is 6-8cm diameter (tennis ball size) for standard varieties. Bulb should feel firm and smooth. Harvest promptly. Overgrown bulbs (>10cm for standard varieties) become woody and fibrous. Exception: Superschmelz stays tender up to 20cm.

How to harvest: Cut stem just below the bulb with a sharp knife, or pull the entire plant. Trim off leaves (save for cooking, they are edible). Trim the root.

Where to next

What kohlrabi costs in the shops right now, retailer by retailer, updated daily.

Also worth sowing in the tropical zone this September: Lemongrass, Ginger, Cucumber and Basil.

The pest most likely to find your kohlrabi: Cabbage White Butterfly.

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Common Questions About Kohlrabi

When do you plant kohlrabi in Australia?

It depends on your climate zone, not the calendar month alone. Planting months by zone:

Does kohlrabi grow all year round in Cairns?

No. In the Tropical zone the planting months are Mar to Aug. Outside that window it either bolts, sulks or gets cut down by the weather.

Which zone am I in?

Type your postcode into the box under the heading and the page tells you, and links this crop in your own zone if it differs. Or look it up on the grow zone map. This page is the Tropical zone, Cairns is its reference city.