When to Plant Tree Onion in Cairns, Tropical Guide
What this month normally looks like in Tropical
In October the Tropical zone normally runs 34°C by day and 23°C overnight, with about 53 mm of rain over 5 or 6 wet days. Averages 1991 to 2026, 37 postcodes, SILO.
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This Tree Onion guide is written for the Tropical zone, which takes in Cairns, Townsville and Darwin. Somewhere else? Your postcode picks the right one.
Not your zone? Brisbane Sydney Melbourne Canberra Alice Springs Perth
Also handy: will it frost this week? and what grows in shade.
- Planting window
- May to Aug
- 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 Tropical
- Jan -
- Feb -
- Mar -
- Apr -
- May P
- Jun P
- Jul P
- Aug P
- Sep -
- Oct -
- Nov -
- Dec -
P = Planting window
You might be able to grow it here under the right conditions. Plant bulbils May to August in the dry season, 3 cm deep and 15 to 20 cm apart (Green Harvest). It is the most cold-hardy onion (Green Harvest) and no source covers the tropics; the wet season will rot the bulbs. Months derived.
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How to Grow Tree Onion in Tropical 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
Tropical Growing Tips for Tree Onion
Recommended Varieties
- Tree onion (Green Harvest)
Key Challenges
- Wet season rot
Pro Tips
- Dry season only, raised bed
Pests and problems for Tree Onion in Tropical
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 Cairns?
You might be able to grow it here under the right conditions. Plant bulbils May to August in the dry season, 3 cm deep and 15 to 20 cm apart (Green Harvest). It is the most cold-hardy onion (Green Harvest) and no source covers the tropics; the wet season will rot the bulbs. 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 Cairns?
Recommended varieties for the Tropical zone include: Tree onion (Green Harvest).
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 Tropical zone, Cairns is its reference city.