When to plant Amaranth in Subtropical Australia
Subtropical zone — applies to Brisbane, Gold Coast, Sunshine Coast, Coffs Harbour, Lismore and similar areas. Growing elsewhere? Temperate · Cool · Tropical · Arid.
Sow amaranth direct from August through to April, scattering the tiny seed just 5 mm deep into warm soil once the mornings lose their chill. It germinates fast, in 5–20 days, and races to a harvest of leaves or grain in 50–60 days. Thin or space plants to about 50 cm, with rows 50–80 cm apart, as a mature plant grows tall and broad. Amaranth loves subtropical heat and humidity, which suits gardens around Brisbane and the Sunshine Coast where crops that struggle in the wet season tend to sulk. Grow it for tender greens, seed, or simply its upright ruby colour.
Sowing calendar — subtropical zone
Green months are your sowing window: August to April.
Growing notes
Amaranth is one of the few leafy crops that positively enjoys a Lismore summer, standing up to heat and downpours that flatten lettuce and spinach. That resilience is the reason to grow it, but a couple of things still trip gardeners up.
The most common failure is bolting mistaken for failure. Amaranth wants to flower and set seed, and once it shifts to a seed head the lower leaves toughen. If you are growing it for greens, harvest young and often by pinching the top 15 cm, which also forces bushier regrowth. If you want grain, let a few plants run to full seed heads and dry them off before the next rain band arrives.
Self-seeding is the other watch point. A single plant sheds thousands of seeds and volunteers can carpet a bed the following season. Cut and remove seed heads before they shatter if you would rather not have a permanent colony.
Slugs and snails can shred seedlings after storms, so protect the youngest plants until they are 10 cm tall and past the vulnerable stage.
Amaranth at a glance
| Sowing depth | 5 mm |
|---|---|
| Plant spacing | 50 cm |
| Row spacing | 50-80 cm |
| Germination | 5-20 days |
| Days to maturity | 50-60 days |
| Frost tolerance | Frost Tender |
| Method | Sow Direct |
Common questions
- Can you grow amaranth in the subtropics over summer
- Yes, amaranth is one of the best hot-weather leafy crops for subtropical gardens. It thrives in the heat and humidity that flatten lettuce and spinach, so it is a reliable summer green around Brisbane and the Sunshine Coast.
- How do you harvest amaranth leaves
- Pinch out the top 15 cm of tender growth while the plant is young. Regular picking keeps it bushy and delays the seed head, which is when the lower leaves start to toughen.
- How long does amaranth take to grow
- Amaranth is quick, maturing in 50–60 days from a sowing that germinates in just 5–20 days. That fast turnaround lets you fit several crops into the long subtropical warm season.
- Does amaranth self-seed
- Heavily. One plant can shed thousands of seeds and volunteer freely the next season. Cut and remove the seed heads before they shatter if you want to keep it contained.
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