Tropical
Open climate guide →JanWaitFebWaitMarPlantAprPlantMayPlantJunPlantJulWaitAugWaitSepWaitOctWaitNovWaitDecWait
Aim for March, April, May, June.
Grow to Eat
When to plant Brown onion in Australia
A practical climate-by-climate planting calendar plus detailed starting, care, problem and safety guidance.
StartSow or transplantLightFull sunTiming20–28 weeksDifficultyModerate
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Australian planting calendar
Best months by climate
Highlighted months are the usual planting window. A local nursery, seed packet and current weather forecast should take priority over a broad climate calendar.
Subtropical
Open climate guide →JanWaitFebPlantMarPlantAprPlantMayPlantJunPlantJulPlantAugWaitSepWaitOctWaitNovWaitDecWait
Aim for February, March, April, May, June, July.
Warm temperate
Open climate guide →JanWaitFebPlantMarPlantAprPlantMayPlantJunPlantJulPlantAugWaitSepWaitOctWaitNovWaitDecWait
Aim for February, March, April, May, June, July.
Cool temperate
Open climate guide →JanWaitFebWaitMarPlantAprPlantMayPlantJunPlantJulPlantAugPlantSepWaitOctWaitNovWaitDecWait
Aim for March, April, May, June, July, August.
Mediterranean
Open climate guide →JanWaitFebPlantMarPlantAprPlantMayPlantJunPlantJulPlantAugWaitSepWaitOctWaitNovWaitDecWait
Aim for February, March, April, May, June, July.
Semi-arid
Open climate guide →JanWaitFebPlantMarPlantAprPlantMayPlantJunPlantJulPlantAugWaitSepWaitOctWaitNovWaitDecWait
Aim for February, March, April, May, June, July.
Arid
Open climate guide →JanWaitFebPlantMarPlantAprPlantMayPlantJunPlantJulPlantAugWaitSepWaitOctWaitNovWaitDecWait
Aim for February, March, April, May, June, July.
Start well
Plant brown onion with confidence
Sow or transplant. Sow about 5–10 mm, using clean seed-raising mix for trays and keeping the surface evenly moist until established.
- Sowing or planting depth
- about 5–10 mm
- Germination or establishment
- Commonly 7–21 days, but the seed packet and current soil temperature are the best guide for the exact variety.
- Spacing
- 8–12 cm
- Soil
- Loose, stone-free soil that drains freely; usually ph 6.0–7.0.
Feeding
Support steady growth
Use mature compost and avoid excessive nitrogen, which can favour leaves over roots.
Water
Keep moisture balanced
Water consistently while roots swell, without leaving the bed waterlogged.
Maintenance
What to do as it grows
Weed carefully because shallow roots dislike competition, and reduce watering as bulbs approach maturity.
Harvest or display
Know when it is ready
20–28 weeks. Readiness varies with variety and weather; use colour, firmness, size and the supplier's maturity notes rather than the calendar alone.
Problems and companions
Keep your patch healthy
Common watch-outs
Look for thrips, onion maggot and basal rot. Free drainage and rotation are more useful than heavy feeding late in the season.
Useful neighbours
Often grown beside carrots, beetroot, lettuce and brassicas. Keep away from peas and beans where close spacing would restrict their growth.
People and pets
Safety note
Onion plant material can poison cats and dogs if eaten. Keep bulbs and scraps inaccessible.
Moving plants
Biosecurity note
Check local weed, invasive-plant and interstate quarantine rules before sharing or moving unfamiliar plant material.
Transparent guidance
How to use this guide
Patch gives a broad Australian starting point, not a guarantee for every variety or garden. Read the Patch methodology and sources, check the latest Bureau of Meteorology climate information, and confirm interstate restrictions through Australian Interstate Quarantine.
Last reviewed 3 September 2026