When to Plant Amaranth in Sydney, Warm Temperate Guide

Sow September to March. Right now in September you can sow.

This Amaranth guide is written for the Warm Temperate zone, which takes in Sydney, Newcastle and Wollongong. Somewhere else? Your postcode picks the right one.

Not your zone? Cairns Brisbane 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 Warm Temperate

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

S = Seed Tray   T = Transplant   D = Direct Sow

Want a nudge when it is Amaranth sowing time in Sydney?

One email a week with what is worth planting in the Warm Temperate zone right now, Amaranth included, plus which veg has jumped in price at the supermarket. Free, and you can stop it in one click.

Current Growing Conditions

Soil temperature: 17.0°C (optimal range: 18–35°C) ✗ Outside optimal range

Modelled from Open-Meteo forecast (Sydney), not a live sensor.

How to Grow Amaranth in Warm Temperate Australia

When to Plant

Sow October-January after soil warms to 18C+. Short growing season compared to tropics. Start in trays indoors from September.

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

Warm Temperate Growing Tips for Amaranth

Recommended Varieties

  • Red Leaf Amaranth
  • Alegria (grain)
  • Golden Giant

Key Challenges

  • Short season limits grain production
  • Cool nights can slow growth in spring and autumn
  • Less vigorous than in warmer zones

Pro Tips

  • Start seeds indoors on heat mat for earlier transplanting
  • Use black plastic mulch to warm soil faster in spring
  • Focus on leaf varieties rather than grain types for reliable harvest

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 Warm Temperate Zones

Aphids and Whiteflies, risk: MODERATE (score: 41/100)

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 warm temperate zone this September: Ginger, Beetroot, Chilli Peppers and Cucumber.

Get the Full Interactive Guide

Track your garden, get real-time pest alerts, and plan around your zone's weather.

Open the planting dashboard Join Garden Buddy

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 Sydney?

No. In the Warm Temperate zone the planting months are Jan to Mar, Sep 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 Warm Temperate zone, Sydney is its reference city.