When to Plant Kohlrabi in Sydney — Warm Temperate Guide

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

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

S = Seed Tray   T = Transplant   D = Direct Sow

Current Growing Conditions

Soil temperature: 19.3°C (optimal range: 10–30°C) ✓ Ready to plant

How to Grow Kohlrabi in Warm Temperate Australia

When to Plant

February to October. Year-round except hottest summer weeks. Two main windows: autumn (March-May) and spring (August-October).

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

Warm Temperate Growing Tips for Kohlrabi

Recommended Varieties

  • White Vienna
  • Purple Vienna
  • Kolibri F1
  • Winner

Key Challenges

  • Summer heat causing bolting
  • Caterpillar damage
  • Clubroot in acidic soils

Pro Tips

  • Sydney gardeners enjoy an extended kohlrabi season
  • Spring and autumn crops are best
  • Net against caterpillars - essential for clean crops

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.

Common Kohlrabi Pests in Warm Temperate Zones

Fungal Soft Rot — Risk: MODERATE (score: 53/100)

Organic prevention: Net crops immediately after planting or sowing. Interplant with strong-scented herbs. Inspect leaf undersides for eggs every few days.

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