When to plant onion in Canberra
Onion is cold-hardy, so every date keys off Canberra's frost dates of Oct 10.
Step 1 · Sow
Start seeds indoors
Aug 1 – Aug 22
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Sep 25 – Oct 16
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Dec 24 – Jan 13
Picking runs until conditions turn against the crop.
Window
Days to maturity
90 – 110 d
Canberra's 204-day season leaves this much room.
Onion on Canberra's growing year
Frost-bounded season with crops mapped onto the 12-month axis.
Frost risk Growing Harvest
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
NOV
DEC
FROST
OCT 10
APR 28
Common questions
When will onion be ready to harvest in Canberra?
Expect to harvest from around late December (Dec 24–Jan 13) in Canberra, based on its local frost dates. Confidence 75%.
When should I start onion seeds indoors in Canberra?
Start seeds indoors around early August (Aug 1–Aug 22) in Canberra, based on its local frost dates. Confidence 79%.
When can I transplant onion outdoors in Canberra?
Transplant outdoors around late September (Sep 25–Oct 16) in Canberra, based on its local frost dates. Confidence 81%.
How long is the growing season in Canberra?
Canberra has roughly 204 frost-free days, which is enough time to grow onion to maturity outdoors.
The rule of thumb
Sow onion as soon as the soil is workable — it tolerates cool weather and light frost. Every date on this page is derived from that rule and Canberra's frost dates.
Confidence 83/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.