When to Plant Onion in Perth — Mediterranean Guide
Photo: Wikimedia Commons
Onions are a staple in Australian kitchens and one of the most widely grown alliums in home gardens. Bulb formation is triggered by day length, making variety selection critical based on latitude. Short-day types suit northern Australia, while long-day types perform best in southern regions.
Planting Calendar
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| — | — | — | — | — | — | S/T/D | S/T/D | S/T/D | — | — | — |
S = Seed Tray T = Transplant D = Direct Sow
Current Growing Conditions
Soil temperature: 13.3°C (optimal range: 8–30°C) ✓ Ready to plant
How to Grow Onion in Mediterranean Australia
When to Plant
Sow April-June, transplant June-August. Long-day and intermediate varieties both work well. Harvest November-January.
- Soil
- Well-drained, fertile loam enriched with compost. Avoid heavy clay or freshly manured soil which causes forking and soft bulbs.
- pH Range
- 6.0-7.0
- Sunlight
- Full sun (minimum 6 hours direct)
- Spacing
- 12cm apart, 30cm between rows
- Watering
- Consistent moisture during bulb development. Water deeply once or twice weekly. Reduce watering as tops begin to fall over (curing signal). Overhead irrigation can reduce thrips but increases fungal r
Companion plants: Carrot, Beetroot, Lettuce, Chamomile, Strawberry
Avoid planting near: Beans, Peas, Asparagus, Sage
Mediterranean Growing Tips for Onion
Recommended Varieties
- Pukekohe Long Keeper (long-day)
- Creamgold (intermediate)
- Brown Spanish
- White Spanish
- Red Globe
Key Challenges
- Hot, dry spring causing premature bulbing if not established
- Downy mildew in wet winters
- Storage quality depends on thorough curing
Pro Tips
- Perth and Adelaide latitudes suit long-day varieties well
- Plant early enough for good leaf growth before bulbing starts
- The dry summers are ideal for curing and storing onions
Harvesting Onion
When ready: Tops fall over naturally and begin to yellow. Bulb skin is papery and dry. Neck tissue is thin and soft. Do not push tops over prematurely as this reduces storage life.
How to harvest: Loosen soil with a fork and lift gently. Do not pull by the tops. Lay on their side in the garden for 1-2 days if weather is dry, then move to a well-ventilated, shaded area for 2-4 weeks to cure fully. Roots and tops are trimmed after curing.
Common Onion Pests in Mediterranean Zones
Organic prevention: Rotate allium crops on a 3-year cycle. Remove crop residues after harvest. Avoid planting near cereal crops which harbour thrips. Maintain weed-free beds.
Supermarket Price
Current average retail: $3.08/kg (12-month range: $0.99–$9.78)
Grow your own and save on grocery bills.
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