When to plant Carrot in Subtropical Australia

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

Carrots are sown direct in the subtropical zone from February through November — essentially any month outside the storm-soaked height of summer. Seed goes just 4 mm deep and is slow to get moving: allow 10–20 days for germination and 70–120 days to a usable root. What separates good carrot growers from frustrated ones is keeping that shallow seed bed constantly damp for the entire germination stretch; a plank or length of shadecloth laid over the row until shoots appear works well in a warm Coffs Harbour autumn. Never transplant carrots — disturbed seedlings fork and twist.

Sowing calendar — subtropical zone

Green months are your sowing window: February to November.

Growing notes

Carrots are half hardy, so the mild subtropical winter barely registers — a June sowing in Brisbane simply takes longer to size up than an autumn one. The excluded months tell the real story: December and January are left out because storm-season downpours crust the soil over germinating seed, rot slow-emerging seedlings and split any roots approaching maturity. Autumn is the prime window, with February–May sowings growing through the most settled weather of the year.

Soil preparation decides the harvest before seed even goes in. Dig deep, break up clods, and never sow into freshly manured ground — excess nitrogen and lumpy organic matter produce the classic forked, hairy roots. Heavier coastal soils around Lismore grow better carrots in raised beds, or with a short stump-rooted variety. Thin seedlings ruthlessly to 3–8 cm; crowded carrots stay pencil-thin no matter how long you wait.

The most common failure here is a bed that never comes up at all. Subtropical sun bakes a crust onto bare soil within a day or two, and seed sitting 4 mm down cannot push through it. Water gently every day — twice in warm spells — and keep the row shaded until germination finishes, which can take nearly three weeks.

Carrot at a glance

Companion planting

Grows well with

Tomatoes: Loosen soil around tomato roots

Chives: Deters carrot fly with strong scent

Leeks: Classic pairing — carrot fly repelled by leek, leek fly repelled by carrot

Keep away from

Dill: Cross-pollinate and hybridise if both allowed to flower; mature dill stunts carrot growth

Dill: Dill and carrot cross-pollinate; mature dill stunts carrot growth

Common questions

When should I sow carrots in Brisbane?

Sow direct from February to November. Autumn sowings from February to May are the sweet spot, growing through settled weather; only the wet, stormy December–January period is off the table.

Why are my carrots forked and twisted?

Forking is caused by fresh manure, stony or cloddy soil, or transplanting. Sow direct into deep, loose, well-dug soil that was manured for a previous crop, not this one.

Why didn't my carrot seed germinate?

Carrot seed sits only 4 mm deep and takes 10–20 days to germinate, so a soil surface that dries or crusts kills it. Water gently daily and shade the row until seedlings are through.

Can I grow carrots over summer in the subtropics?

The window closes for December and January, when storm rain rots seed and splits maturing roots. Resume sowing in February.

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