When to plant Broccoli in Subtropical Australia

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

Direct-sow broccoli from February through May in the subtropical zone, starting as the worst of the summer humidity eases. On the Gold Coast and around Brisbane this autumn window sets heads to form through the cool, dry heart of winter, which is exactly when broccoli is at its best. Seed germinates in 15 to 25 days, and depending on variety you'll cut a central head somewhere between 60 and 120 days from sowing. Sow shallowly, about 6 mm deep, and allow 35–45 cm between plants — crowded broccoli tends to produce small, loose heads instead of a tight central dome.

Sowing calendar — subtropical zone

Green months are your sowing window: February to May.

Growing notes

Broccoli is frost-hardy and genuinely thrives in the mild subtropical winter, but timing at the edges of the window is everything. A February sowing races the tail of the wet season, so seedlings can sit in warm, sodden soil and rot at the collar — hold off until the ground drains if storms are still rolling through. A May sowing is safer, but heads may mature into early spring, so lean on a faster variety at that end.

Cabbage white butterfly is the defining pest here. Through the warm months their green caterpillars will strip leaves and bore into developing heads within days, so drape fine exclusion netting over the bed from transplant onward and check leaf undersides for clustered yellow eggs.

Give broccoli deep, rich, well-limed soil, full sun, and even moisture, since erratic watering causes hollow or bitter stems. In humid spells watch for downy mildew and black rot — water at the base, keep airflow between plants, and remove yellowing lower leaves promptly. Cut the central head while the buds are still tight and dark green, then leave the plant in place to throw smaller side shoots for several more weeks.

Broccoli at a glance

Companion planting

Grows well with

Marigold: Deters cabbage moth and aphids

Nasturtiums: Trap crop for cabbage white butterfly caterpillars

Marigold: Deters cabbage moth; attracts parasitic wasps

Keep away from

Tomatoes: Brassicas and tomatoes compete for same nutrients; inhibit each other

Tomatoes: Brassicas inhibit tomato growth; compete for nutrients

Strawberries: Brassicas inhibit strawberry growth

Common questions

When is the best time to sow broccoli in subtropical Queensland?

Sow direct from February to May. An autumn start lets the heads form through the dry, cool winter, which gives the tightest, sweetest broccoli.

How do I stop caterpillars eating my broccoli?

The culprit is usually the cabbage white butterfly. Cover the bed with fine exclusion netting from the seedling stage and squash any rows of yellow eggs you find under the leaves.

Why are my broccoli heads small and loose?

This usually comes from crowding, heat, or uneven watering. Space plants 35–45 cm apart, sow early enough to head up in the cool months, and keep the moisture steady.

Will broccoli grow back after I cut the main head?

Yes. Leave the plant in the ground after cutting the central head and it will produce smaller side shoots for several weeks.

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