When to Plant Amaranth in Canberra — Cold / Highland Guide

Amaranth

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: 18.9°C (optimal range: 18–35°C) ✓ Ready to plant

How to Grow Amaranth in Cold / Highland Australia

When to Plant

December-January only, if at all. Better grown as microgreens or indoor sprouts year-round.

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

Cold / Highland Growing Tips for Amaranth

Recommended Varieties

  • Red Leaf Amaranth (microgreens only practical)

Key Challenges

  • Frost kills plants instantly
  • Season too short for meaningful outdoor production
  • Cool temperatures inhibit germination

Pro Tips

  • Grow as microgreens on a sunny windowsill year-round
  • If attempting outdoors, use cloches or cold frames from November
  • Focus on other leafy greens better suited to cold climates

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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