When to plant Mint in Temperate Australia

Temperate zone — applies to Sydney, Melbourne, Adelaide, Perth, Newcastle and similar areas. Growing elsewhere? Cool · Subtropical · Tropical · Arid.

Raise mint from seed in punnets from August to December in temperate Australia, then transplant seedlings out once they are sturdy. Seed is tiny and goes on at just 2 mm deep, germinating in 7–21 days, with plants reaching harvest size about 90 days from sowing. Mint is hardy, so frost is no obstacle — the bigger question is where to put it, because it spreads aggressively by underground runners. Allow 30–50 cm between plants, give it moisture and a little shade, and strongly consider a pot or a root barrier before it decides your whole bed belongs to it.

Sowing calendar — temperate zone

Green months are your sowing window: August to December.

Growing notes

Being fully hardy, mint treats the temperate frost season — roughly May to mid-October — as a rest rather than a threat. Top growth dies back in cold winters, but the roots persist and reshoot vigorously in spring. Seed sown in punnets in August and September will have well-rooted seedlings ready to plant out mid-spring; later sowings through to December still establish comfortably before their first winter.

Surface-sow the fine seed at barely 2 mm, keep punnets moist and expect germination across 7–21 days. Transplant at 30–50 cm spacing into moist, rich soil. Unlike most herbs, mint prefers damp conditions and tolerates — even appreciates — part shade; a dry, baking position gives sparse, harsh-flavoured leaves.

The great mint failure is not growing it, but containing it. Its runners travel under mulch and paths and emerge metres away, and once entrenched among other perennials it is very hard to remove. Grow it in a large pot, a sunken barrier or a dedicated corner from day one.

• Keep soil consistently moist through summer
• Cut back hard several times a season to force fresh, tender growth
• Renew container plants every couple of years when roots choke the pot
• Watch for orange pustules of mint rust and remove affected stems promptly

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 temperate Australia?

Raise seed in punnets from August to December and transplant once seedlings are sturdy. Mint is hardy, so spring plantings establish easily and survive winters without protection.

How long does mint take to grow from seed?

Germination takes 7–21 days and plants reach harvest size around 90 days from sowing. Once established, mint regrows quickly after each cutting.

How do I stop mint taking over my garden?

Grow it in a large pot or behind a solid root barrier. Mint spreads by underground runners that travel surprising distances, and it is far easier to contain from the start than to remove later.

Does mint die back in winter?

In frosty temperate areas the top growth often dies back over winter, but the roots are hardy and the plant reshoots strongly in spring.

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