When to plant Potato in Tropical Australia

Tropical zone — applies to Darwin, Cairns, Townsville, Broome, Mackay and similar areas. Growing elsewhere? Temperate · Cool · Subtropical · Arid.

Plant seed potatoes directly into the ground from March to October, through the dry season when tubers can bulk up without sitting in monsoon-soaked soil. Shoots take 14 to 28 days to break the surface, and the crop needs a long run of 105 to 140 days to size up, so plant early in the window rather than late. Set tubers 30 to 50 mm deep and 30 to 40 cm apart, with 60 cm between rows. Use certified seed potatoes rather than supermarket ones, which are often treated to suppress sprouting and can carry disease into tropical beds around Mackay and Cairns.

Sowing calendar — tropical zone

Green months are your sowing window: March to October.

Growing notes

Potatoes belong firmly in the dry season here. Tubers left in the ground as the wet arrives simply rot, so aim to lift the crop before the monsoon breaks — an early-to-mid dry-season planting gives the 105-to-140-day crop time to finish.

The single most important job is hilling. As shoots reach 20 to 25 cm, draw soil up around the stems, and repeat every couple of weeks. This buries developing tubers, stops them greening, and gives the plant more room to set a heavier crop. Grow in free-draining, slightly acidic soil enriched with compost but not fresh manure, which encourages scab.

Watering matters through the season: keep the soil evenly moist while plants flower and tubers swell, then ease off as the foliage yellows so skins can firm before harvest. Overwatering in warm soil invites rot. The common tropical failure is exactly that rot and disease — bacterial wilt and soft rot spread fast in warm, wet ground, and blight can strike where humidity is high. Choose certified disease-free seed, avoid low-lying waterlogged spots, and never plant where tomatoes, capsicum or eggplant grew recently, since they share the same soil-borne diseases.

Potato at a glance

Companion planting

Grows well with

Marigold: Deters potato beetle and nematodes

Nasturtiums: Lures aphids and beetles away from potato

Horseradish: Traditional claim: deters potato beetle; limited trial evidence

Keep away from

Tomatoes: Both susceptible to blight; growing together increases disease spread risk

Cucumber: Both attract similar pests; disease spread risk

Common questions

When should I plant potatoes in the tropics?

Plant seed potatoes from March to October, early enough in the dry season that the 105-to-140-day crop can be lifted before the wet season returns.

Why did my potatoes rot in the ground?

Warm, waterlogged soil causes soft rot and bacterial wilt. Plant on free-draining, raised ground, ease off watering as foliage yellows, and harvest before the monsoon.

Can I use supermarket potatoes for planting?

It is best avoided. Shop potatoes are often sprout-treated and can introduce disease. Certified seed potatoes give more reliable sprouting and cleaner crops.

Do I need to hill up potatoes?

Yes. Draw soil up around the stems once shoots reach 20 to 25 cm and repeat as they grow, to bury tubers, prevent greening and lift yields.

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