When to plant Mustard in Tropical Australia

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

Mustard can be sown direct in the tropics in any month of the year, dropping seed 6 mm deep into moist, fertile soil for a fast, peppery leaf crop. It germinates in 6 to 12 days and matures in 30 to 60 days depending on whether you cut it young or grow it on. Space plants 30 to 40 cm apart with rows 40 to 60 cm apart for full-sized heads, or sow thicker for baby leaves. Hardy and untroubled by frost, mustard is adaptable across the tropical calendar, but heat and wet-season humidity push it to bolt, so the cooler dry-season months around Darwin, Townsville and Cairns give the mildest, most productive crop.

Sowing calendar — tropical zone

Green months are your sowing window: January to December.

Growing notes

Mustard is a quick, hot-flavoured leafy brassica that suits tropical gardens because it crops fast enough to fit between the seasonal extremes. Although it can be sown any month, the cool dry season gives the best flavour and the slowest bolting, while the peak wet brings heat stress and pests.

Grow it in rich, moisture-retentive soil with steady watering. Any check from dry soil or heat makes the leaves hotter and hastens flowering, so consistency is the goal. A little afternoon shade helps during the humid build-up.

The main failure mode is bolting in the heat. When temperatures climb and the wet arrives, mustard shoots up a flower stalk and the leaves turn fiercely pungent and tough. The fix is to grow the main crops in the cool dry season, water reliably, and harvest young by cutting outer leaves before any flower stalk forms. Caterpillars and flea beetle also favour mustard; a fine mesh cover keeps them off, and because mustard is a fast brassica, rotating it around the garden helps break pest and disease cycles. If plants start to bolt, harvest everything at once, as the whole plant remains usable cooked even when the raw leaves have turned sharp.

Mustard at a glance

Common questions

When is the best time to grow mustard in the tropics?

Although mustard can be sown any month, the cool dry season gives the mildest flavour and the slowest bolting. The hot, humid wet season around Darwin and Cairns pushes plants to flower quickly and turns the leaves fiercely hot.

Why are my mustard leaves so hot and tough?

Heat, dry soil and bolting all intensify the pepperiness and toughen the leaves. Keep the soil consistently moist, harvest young, and grow your main crop in the cooler dry-season months for milder greens.

How far apart should mustard be planted?

Space plants 30 to 40 cm apart with rows 40 to 60 cm apart for full-sized plants, or sow more thickly and harvest as baby leaves. Wider spacing improves airflow, which helps in humid tropical conditions.

What eats holes in mustard leaves?

Caterpillars and flea beetle are the usual culprits on mustard and other brassicas. Cover the crop with fine insect mesh and rotate mustard around the garden each season to break the pest cycle.

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