When to plant Cauliflower in Subtropical Australia

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

Sow cauliflower direct from March right through to July, giving it the long, cool run it needs in the subtropics. This is the most demanding of the brassicas and the least forgiving of heat, so the autumn-to-winter window around Brisbane and the Sunshine Coast suits it well. Seed comes up in about 6 to 12 days, but be patient afterwards — cauliflower is slow, taking anywhere from 100 to 160 days to form a full curd. Sow 6 mm deep and give each plant generous room, 45–70 cm apart, because a stressed or crowded plant will 'button' into a tiny, premature head.

Sowing calendar — subtropical zone

Green months are your sowing window: March to July.

Growing notes

Cauliflower's long season is the real challenge in a subtropical garden: sow too late and the curd tries to form as spring warms, which browns and loosens it. An early autumn sowing in March or April is the safest bet, letting the plant do most of its growing through the reliably cool, dry midwinter. Any check to growth — a dry spell, a warm snap, or root disturbance — can trigger buttoning, so keep water and feeding steady from the very start.

Like all brassicas it is a magnet for cabbage white butterfly, whose caterpillars hide deep in the developing curd where they are hard to spot and harder to wash out. Net the bed from the moment seedlings emerge and inspect it regularly.

Plant into firm, deeply worked soil rich in nitrogen and lime, in full winter sun. Once the curd reaches egg size, snap a few outer leaves over it to blanch the head and keep it from yellowing in the light. In humid weather, strip away lower leaves that touch the soil to cut the risk of fungal rot creeping up into the curd, and never let the bed swing between bone-dry and waterlogged.

Cauliflower at a glance

Companion planting

Grows well with

Nasturtiums: Trap crop; deters cabbage white butterfly

Marigold: Deters aphids and cabbage moth

Common questions

When should I plant cauliflower in the subtropics?

Sow direct from March to July. An early autumn start is best, as it gives the slow-growing curd the full cool winter to develop before spring warmth arrives.

Why did my cauliflower form a tiny head?

That is 'buttoning', caused by a check to growth such as heat, dryness, or transplant shock. Sow early, keep water and feed consistent, and avoid disturbing the roots.

How long does cauliflower take to grow?

It is a long crop, taking roughly 100 to 160 days from sowing to a mature curd, so plan the bed around that timeframe.

How do I keep my cauliflower curd white?

Once the curd reaches egg size, bend a few outer leaves over it to shade and blanch the head. This stops it yellowing in the sun.

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