When to Plant Watermelon in Brisbane, Subtropical Guide

Sow July to January. Right now in September you can sow.

Published · Last reviewed · By Garden Buddy
Growing advice is reviewed by hand. Planting dates, current conditions and prices on this page update daily.

This Watermelon guide is written for the Subtropical zone, which takes in Brisbane, the Gold Coast and the Sunshine Coast. Somewhere else? Your postcode picks the right one.

Not your zone? Cairns Sydney Melbourne Canberra Alice Springs Perth

Also handy: will it frost this week? and what grows in shade.

Watermelon

Photo: Wikimedia Commons

Watermelon is a warm-season vine crop native to Africa, requiring long hot summers and ample space. Australia's arid interior and northern regions produce some of the sweetest watermelons in the world. Home-grown watermelon in warm zones is deeply rewarding. Requires substantial space (each vine can spread 3-4m), consistent warmth, and patience (80-100+ days to maturity).

Planting Calendar for Subtropical

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
T - - - - - S S S/T/D S/T/D T/D T

S = Seed Tray   T = Transplant   D = Direct Sow

Want a nudge when it is Watermelon sowing time in Brisbane?

One email a week with what is worth planting in the Subtropical zone right now, Watermelon included, plus which veg has jumped in price at the supermarket. Free, and you can stop it in one click.

Current Growing Conditions

Soil temperature: 20.4°C (optimal range: 21–35°C) ✗ Outside optimal range

That figure is read off my own weather station here at Dayboro in South East Queensland at 18:55 yesterday, not a model. The radar, the rain gauge and the forecasts behind it sit on Dayboro.au.

How to Grow Watermelon in Subtropical Australia

When to Plant

September to December. Long season needed.

Soil
Sandy loam to loam, well-drained, enriched with compost. Sandy soils warm fastest. Watermelons tolerate slightly sandier conditions than most cucurbits.
pH Range
6.0-7.0
Sunlight
Full sun (minimum 8 hours). More heat and sun = sweeter fruit.
Spacing
150cm apart, 250cm between rows
Watering
Deep regular watering during vine growth and fruit development. CRITICAL: reduce watering 2 weeks before harvest to concentrate sugars. Excess water at maturity dilutes sweetness and causes splitting.

Companion plants: Corn, Sunflower, Nasturtium, Radish (trap crop for flea beetles)

Avoid planting near: Potato, Other Citrullus if seed saving

Subtropical Growing Tips for Watermelon

Recommended Varieties

  • Crimson Sweet
  • Sugar Baby
  • Moon and Stars
  • Ali Baba
  • Jubilee

Key Challenges

  • Fruit fly
  • Space requirements
  • Powdery mildew late season

Pro Tips

  • Needs the full summer heat period
  • Sugar Baby is compact (2-4kg fruit) for smaller gardens
  • Reduce watering 2 weeks before harvest

Harvesting Watermelon

When ready: Multiple indicators needed: 1) Tendril nearest fruit turns brown and dry, 2) Ground spot (where fruit sits) turns from white to creamy yellow, 3) Skin resists thumbnail scratch (hard rind), 4) Dull thud when tapped (not hollow ring). Use ALL indicators together. No single one is reliable alone.

How to harvest: Cut stem cleanly with sharp knife. Do not pull or twist. Handle carefully.

Worth growing?

A 2.4 m × 1.2 m bed fits 1 plant, about $14 worth at today’s Aldi prices, checked today.

That is roughly 4 kg at $3.49 a kilo.

Draw your watermelon bed → No account needed.

Common Watermelon Pests in Subtropical Zones

Fungal Infections, risk: LOW (score: 36/100)

Organic prevention: Net before ripening. Hygiene. Thick-rind varieties less susceptible.

View all pest alerts →

Where to next

What watermelon costs in the shops right now, retailer by retailer, updated daily.

Also worth sowing in the subtropical zone this September: Lemongrass, Ginger, Beetroot and Chilli Peppers.

The pest most likely to find your watermelon: Downy Mildew.

Supermarket Price

Current average retail: $3.49/kg (12-month range: $3.49–$3.99)

Grow your own and save on grocery bills.

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Common Questions About Watermelon

When do you plant watermelon in Australia?

It depends on your climate zone, not the calendar month alone. Planting months by zone:

Does watermelon grow all year round in Brisbane?

No. In the Subtropical zone the planting months are Jan, Jul to Dec. Outside that window it either bolts, sulks or gets cut down by the weather.

Which zone am I in?

Type your postcode into the box under the heading and the page tells you, and links this crop in your own zone if it differs. Or look it up on the grow zone map. This page is the Subtropical zone, Brisbane is its reference city.