When to Plant Spinach in Cairns — Tropical Guide
Photo: Wikimedia Commons
True spinach (English spinach) is a cool-season annual prized for its tender, dark green leaves. It is one of the most nutritious leafy greens but also one of the most temperamental to grow in Australian conditions. It bolts rapidly in heat and long day-lengths, making it primarily an autumn-winter-early spring crop across most of Australia. Understanding this limitation is key to successful growing.
Current Growing Conditions
Soil temperature: 25.2°C (optimal range: 4–25°C) ✗ Outside optimal range
How to Grow Spinach in Tropical Australia
When to Plant
June-August at best, but true spinach is poorly suited to tropical conditions. Bolts within weeks. Not recommended.
- Soil
- Rich, well-drained soil heavily enriched with compost and well-rotted manure. Spinach is a heavy feeder that demands fertile soil.
- pH Range
- 6.0-7.5
- Sunlight
- Full sun in cool weather. Part shade beneficial in all but the coldest zones. Shade delays bolting.
- Spacing
- 20cm apart, 30cm between rows
- Watering
- Consistent moisture essential. Light, frequent watering keeps soil evenly moist. Drought stress triggers bolting. Morning watering. Drip irrigation ideal.
Companion plants: Strawberry, Pea, Bean, Celery, Cauliflower, Radish
Avoid planting near: Beetroot (same family; shared pests and diseases)
Tropical Growing Tips for Spinach
Recommended Varieties
- Not recommended. Use NZ spinach, amaranth, or kangkung as substitutes.
Key Challenges
- Bolts almost immediately in tropical warmth
- Downy mildew in humidity
- Genuinely impractical crop
Pro Tips
- Do not grow true spinach in the tropics. It will fail.
- Grow NZ spinach (warrigal greens) instead - it thrives in tropical heat
- Kangkung (water spinach) is another excellent tropical substitute
Harvesting Spinach
When ready: Baby spinach: leaves 5-8cm (3-4 weeks). Full size: leaves 15-20cm (6-8 weeks). Leaves should be dark green, firm, and glossy. Harvest before any sign of flower stalk elongation.
How to harvest: Cut-and-come-again: cut outer leaves at base, leaving inner leaves and growing point. Or cut entire plant 3cm above ground for one large harvest (may regrow once). Harvest in cool of morning.
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