When to Plant Amaranth in Cairns — Tropical Guide
Photo: Wikimedia Commons
Amaranth is a heat-loving leafy green and grain crop originating from Central America, now widely grown across tropical and subtropical Australia. Leaf amaranth varieties produce abundant, nutritious greens rich in iron, calcium and vitamins A and C. It thrives where lettuce and spinach bolt, making it the go-to summer green for warm climates.
Current Growing Conditions
Soil temperature: 25.2°C (optimal range: 18–35°C) ✓ Ready to plant
How to Grow Amaranth in Tropical Australia
When to Plant
Year-round growing possible but best from March-August (dry season). Wet season growing challenging due to fungal pressure. Sow direct after monsoon rains ease.
- Soil
- Well-drained, fertile loam enriched with compost. Tolerates a wide range of soils including sandy and clay, provided drainage is adequate.
- pH Range
- 6.0-7.5
- Sunlight
- Full sun (minimum 6-8 hours). Will tolerate light afternoon shade in extreme heat.
- Spacing
- 25cm apart, 45cm between rows
- Watering
- Water deeply 2-3 times per week once established. Drought tolerant once mature but produces best leaf quality with consistent moisture. Avoid waterlogging. Drip irrigation preferred.
Companion plants: Corn, Tomato, Eggplant, Lettuce (amaranth provides shade), Marigold
Avoid planting near: Brassicas (nutrient competition), Fennel
Tropical Growing Tips for Amaranth
Recommended Varieties
- Red Leaf Amaranth (Amaranthus tricolor)
- Joseph's Coat
- Edible Red
- Callaloo (Caribbean leaf type)
Key Challenges
- Fungal diseases in wet season humidity
- Caterpillar pressure year-round
- Seeds may wash away in heavy rain
Pro Tips
- Grow as a wet-season alternative to lettuce and spinach which bolt in tropical heat
- Harvest young leaves frequently (cut-and-come-again) for continuous production
- Raise beds 20-30cm for improved drainage during wet season
Harvesting Amaranth
When ready: Leaf amaranth: harvest when leaves are 10-15cm long for baby greens, or let plants reach 30-40cm for full-size leaves. Grain amaranth: harvest when seed heads droop and seeds fall easily when rubbed.
How to harvest: Cut-and-come-again: cut leaves or tops 10cm above ground level and plants will reshoot. For grain: cut entire seed heads, dry in paper bags, thresh by rubbing between hands.
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