When to plant Mint in Subtropical Australia

Subtropical zone — applies to Brisbane, Gold Coast, Sunshine Coast, Coffs Harbour, Lismore and similar areas. Growing elsewhere? Temperate · Cool · Tropical · Arid.

Mint is raised as seedlings and transplanted out, with sowing from August to November in the subtropical zone. Surface-sow just 2 mm deep, expect germination in 7–21 days, and allow about 90 days before the patch is worth harvesting from — after that it needs no encouragement at all. Unlike the Mediterranean herbs, mint relishes a humid Brisbane or Sunshine Coast summer, growing fastest exactly when rosemary and thyme are struggling. Give transplants 30–50 cm of space, part shade, and steady moisture, and think hard about containment before planting — mint does not stay where it is put.

Sowing calendar — subtropical zone

Green months are your sowing window: August to November.

Growing notes

Mint's calendar runs opposite to most herbs here. The December–February wet, which rots thyme and mildews basil, is mint's peak growing season — warmth plus constant moisture produces the lushest growth of the year. Through the mild coastal winter it barely pauses, staying pickable year-round in Brisbane, though in colder spots inland from Coffs Harbour it thins out until spring.

Spring-sown seedlings transplant best into moist, rich soil in part shade — full afternoon sun in January will scorch it unless water is constant. The real cultural decision is containment: in this climate mint spreads with intent, and runners escape ordinary garden edges within a season. A large pot, or a bed bounded by paving, saves years of pulling it out of everything else.

• Transplant seedlings 30–50 cm apart from spring
• Keep soil constantly moist; potted mint may need daily water in summer
• Cut the whole patch back hard two or three times a year for fresh growth
• Watch for the orange pustules of mint rust in humid weather

Rust is the one disease worth acting on quickly. Cut infected stems to the ground and bin them rather than composting, and the regrowth usually comes back clean — helped along by that hard-cutback habit.

Mint at a glance

Companion planting

Grows well with

Peas: Deters aphids and pea moth

Peas: Deters aphids and pea moth

Cabbage: Strong scent deters cabbage white butterfly

Common questions

When should I plant mint in the subtropical zone?

Sow from August to November, raising seedlings and transplanting them out. Expect germination in 7–21 days and a harvestable patch about 90 days after sowing.

Why does my mint have orange spots under the leaves?

That is mint rust, which thrives in humid weather. Cut affected stems right to the ground and bin them, and the new growth usually emerges clean.

Does mint die back in winter in Brisbane?

Not on the coast — the mild subtropical winter keeps mint pickable year-round in Brisbane. Colder inland gardens see it thin out until spring.

Should I grow mint in a pot?

In the subtropics, almost certainly. Warmth and summer moisture make mint spread aggressively by runners, so a large pot or a paved-in bed keeps it out of the rest of the garden.

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