When to Plant Tree Onion in Canberra, Cold / Highland Guide
What this month normally looks like in Cold / Highland
In October the Cold / Highland zone normally runs 20°C by day and 7°C overnight, with about 58 mm of rain over 7 or 8 wet days. The coldest October night on record across the zone was -6.4°C, so a late frost is not out of the question. Averages 1991 to 2026, 15 postcodes, SILO.
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This Tree Onion guide is written for the Cold / Highland zone, which takes in Canberra, Cooma and Bright. Somewhere else? Your postcode picks the right one.
Not your zone? Cairns Brisbane Sydney Melbourne Alice Springs Perth
Also handy: will it frost this week? and what grows in shade.
- Planting window
- Oct to Dec
- Days to harvest
- about 34 weeks
- Sun
- Full sun
- Water
- Moderate
- Spacing
- 15 cm apart
The tree onion (Egyptian walking onion, topsetting onion) is a hardy perennial onion that grows clusters of 6 to 8 small bulbils on top of its stalks instead of flowers; the stalks topple and the bulbils root where they...
Published · By GardenBuddy.au
Planting dates, current conditions and prices on this page update daily.
Photo: Wikimedia Commons
Best Planting Window for Cold / Highland
- Jan -
- Feb -
- Mar -
- Apr -
- May -
- Jun -
- Jul -
- Aug -
- Sep -
- Oct P
- Nov P
- Dec P
P = Planting window
Plant bulbils in late spring, October to December, once the ground has thawed (Green Harvest cooler-area advice); it is the most cold-hardy onion and will stand frost (Green Harvest). Bulbs ready December to February. Months derived.
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How to Grow Tree Onion in Cold / Highland Australia
- Soil
- Well drained, limed if acid; no fresh manure (Green Harvest).
- Salt
- Moderately sensitive. Copes with a little salt, but the harvest drops on salty bore water.
- pH Range
- Not given by the sources opened; lime acid soil (Green Harvest).
- Sunlight
- Full sun (Organic Gardener).
- Spacing
- 15cm apart, 30cm between rows
- Watering
- Moderate; never waterlogged.
- Good companions
- Lettuce, Tomato, Carrot, Cabbage, Spinach
- Keep away from
- Asparagus, Broad Beans, Climbing Beans, Dwarf Beans, Peas
Cold / Highland Growing Tips for Tree Onion
Recommended Varieties
- Tree onion
Key Challenges
- Frozen ground
Pro Tips
- Plant after thaw
Pests and problems for Tree Onion in Cold / Highland
Harvesting Tree Onion
When ready: Bulbils when the stalks dry off (Green Harvest); bulbs in spring to early summer (Organic Gardener); green tops any time.
How to harvest: Snip tops, lift bulbs, pick bulbil heads (Organic Gardener).
Storing and preserving tree onion
How to keep it
- Drying bulbils. Dry on a screen out of the sun, then store cool and dry (Green Harvest). Keeps: 12 months.
What members get
- Soil and weather from your nearest station
- An email when it's time to sow
- Your own garden plan, including planning from a photo
- Price history and price alerts
- Pest risk alerts for your area
- Full salt and canning detail
Common Questions About Tree Onion
When do you plant tree onion in Australia?
It depends on your climate zone, not the calendar month alone. Planting months by zone:
- Tropical (Cairns): May to Aug
- Subtropical (Brisbane): May to Dec
- Warm Temperate (Sydney): May to Dec
- Cool Temperate (Melbourne): Mar to Apr, Oct to Dec
- Cold / Highland (Canberra): Oct to Dec
- Arid / Semi-Arid (Alice Springs): May to Aug
- Mediterranean (Perth): May to Dec
When should I plant Tree Onion in Canberra?
Plant bulbils in late spring, October to December, once the ground has thawed (Green Harvest cooler-area advice); it is the most cold-hardy onion and will stand frost (Green Harvest). Bulbs ready December to February. Months derived.
How do I know when Tree Onion are ready to harvest?
Bulbils when the stalks dry off (Green Harvest); bulbs in spring to early summer (Organic Gardener); green tops any time.
What are the best Tree Onion varieties for Canberra?
Recommended varieties for the Cold / Highland zone include: Tree onion.
What grows well with Tree Onion?
Good companion plants for Tree Onion include: Lettuce, Tomato, Carrot, Cabbage, Spinach.
Are tree onion salt tolerant?
Only a little. Tree onion are moderately sensitive to salt, so the harvest drops on salty bore water. Mix salty water with rainwater, and mulch the bed.
Which zone am I in?
Type your postcode into the box near the top of the page and it 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 Cold / Highland zone, Canberra is its reference city.