When to Plant Amaranth in Brisbane, Subtropical Guide

Sow August to April. Right now in September you can sow.

Published · Last reviewed · By Garden Buddy
Growing advice is reviewed by hand. Planting dates, current conditions and prices on this page update daily.

This Amaranth guide is written for the Subtropical zone, which takes in Brisbane, the Gold Coast and the Sunshine Coast. Somewhere else? Your postcode picks the right one.

Not your zone? Cairns Sydney Melbourne Canberra Alice Springs Perth

Also handy: will it frost this week? and what grows in shade.

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.

Planting Calendar for Subtropical

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

S = Seed Tray   T = Transplant   D = Direct Sow

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Current Growing Conditions

Soil temperature: 20.4°C (optimal range: 18–35°C) ✓ Ready to plant

That figure is read off my own weather station here at Dayboro in South East Queensland at 18:55 yesterday, not a model. The radar, the rain gauge and the forecasts behind it sit on Dayboro.au.

How to Grow Amaranth in Subtropical Australia

When to Plant

Sow September-March. Peak growing period October-February. Can extend to April with warm autumn. Too cold for germination May-August.

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

Subtropical Growing Tips for Amaranth

Recommended Varieties

  • Edible Red
  • Golden Giant (grain)
  • Red Leaf
  • Joseph's Coat

Key Challenges

  • Flea beetles in warm weather
  • Bolting to seed in late summer heat (harvest young)
  • Drought stress in dry springs

Pro Tips

  • Ideal summer substitute for cool-season greens in SEQ
  • Sow successionally every 3 weeks for continuous baby leaf harvest
  • Mulch heavily to retain soil moisture through dry springs

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.

Common Amaranth Pests in Subtropical Zones

Aphids and Whiteflies, risk: MODERATE (score: 56/100)

Organic prevention: Companion plant with marigolds and basil. Maintain good garden hygiene. Remove amaranth family weeds. Delay planting until soil is warm; vigorous seedlings outgrow damage.

View all pest alerts →

Where to next

Also worth sowing in the subtropical zone this September: Lemongrass, Ginger, Beetroot and Chilli Peppers.

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Common Questions About Amaranth

When do you plant amaranth in Australia?

It depends on your climate zone, not the calendar month alone. Planting months by zone:

Does amaranth grow all year round in Brisbane?

No. In the Subtropical zone the planting months are Jan to Apr, Aug to Dec. Outside that window it either bolts, sulks or gets cut down by the weather.

Which zone am I in?

Type your postcode into the box under the heading and the page tells you, and links this crop in your own zone if it differs. Or look it up on the grow zone map. This page is the Subtropical zone, Brisbane is its reference city.