When to Plant Coriander in Cairns — Tropical Guide

Coriander

Photo: Wikimedia Commons

The most frustrating herb in Australia. Coriander bolts to seed at the first hint of warmth, making it a cool-season-only crop in most zones. Both the leaves (cilantro) and seeds (coriander spice) are useful. Understanding its biology is the key to managing bolting - this is NOT a herb that grows like parsley. It is a rapid-lifecycle annual that wants to flower and die as fast as possible.

Current Growing Conditions

Soil temperature: 25.2°C (optimal range: 10–25°C) ✗ Outside optimal range

How to Grow Coriander in Tropical Australia

When to Plant

Dry season ONLY: April-July. Will bolt within 3-4 weeks in warm months. Sow direct every 2 weeks.

Soil
Rich, well-drained soil with compost. Consistent moisture critical.
pH Range
6.0-7.0
Sunlight
Full sun in cool weather. Part shade essential in warm zones to delay bolting.
Spacing
5cm apart, 20cm between rows
Watering
Keep consistently moist at all times. Any drought stress triggers bolting. Mulch to retain moisture and keep roots cool.

Companion plants: Dill, Chervil, Parsley, Lettuce

Avoid planting near: Fennel

Tropical Growing Tips for Coriander

Recommended Varieties

  • Slow Bolt
  • Leisure (slow bolt variety)
  • Santo

Key Challenges

  • Bolts within weeks of germinating in warm weather
  • Extremely narrow planting window
  • Heat + humidity = rapid flowering

Pro Tips

  • Accept that coriander is a cool-season crop only
  • Sow thickly and harvest as microgreens/baby leaf
  • Use Vietnamese coriander (Persicaria odorata) as a warm-season substitute - it tastes similar and thrives in tropical heat

Harvesting Coriander

When ready: Harvest leaves once plants are 10-15cm tall. Harvest before any sign of central flower stem elongation.

How to harvest: Cut outer leaves at base, leaving central growing point. Or cut entire plant 3cm above soil for regrowth (one regrowth only). For seed: let plants bolt, flower, and set seed until brown.

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