When to Plant Onion in Alice Springs — Arid / Semi-Arid Guide

Onion

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 T T T T/D

S = Seed Tray   T = Transplant   D = Direct Sow

Current Growing Conditions

Soil temperature: 27.9°C (optimal range: 8–30°C) ✓ Ready to plant

How to Grow Onion in Arid / Semi-Arid Australia

When to Plant

Sow March-May (autumn). Grow through the cooler months. Harvest September-November before extreme heat. Short-day to intermediate varieties suit the latitude.

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

Arid / Semi-Arid Growing Tips for Onion

Recommended Varieties

  • Texas Grano (short-day)
  • Gladalan Brown
  • Brown Spanish (intermediate)
  • Red Tropicana

Key Challenges

  • Extreme summer heat preventing bulb development
  • Thrips thrive in hot dry conditions
  • Water management critical

Pro Tips

  • Grow onions as a winter crop only - summer heat is prohibitive
  • Drip irrigation is essential for consistent moisture without wetting foliage
  • Mulch heavily to keep soil cool and retain moisture

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 Arid / Semi-Arid Zones

Downy Mildew — Risk: LOW (score: 32/100)

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.

View all pest alerts →

Supermarket Price

Current average retail: $6.21/kg (range: $1.99–$21.33)

Grow your own and save on grocery bills.

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