When to plant onion in Canberra
Onion is cold-hardy, so every date keys off Canberra's frost dates of Oct 20.
Step 1 · Sow
Start seeds indoors
Aug 11 – Sep 1
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Sep 29 – Oct 20
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Dec 28 – Jan 17
Picking runs until conditions turn against the crop.
Window
Days to maturity
90 – 110 d
Canberra's 182-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 20
APR 20
Common questions
When will onion be ready to harvest in Canberra?
Expect to harvest from around late December (Dec 28–Jan 17) in Canberra, based on its local frost dates. Confidence 74%.
When should I start onion seeds indoors in Canberra?
Start seeds indoors around mid August (Aug 11–Sep 1) in Canberra, based on its local frost dates. Confidence 78%.
When can I transplant onion outdoors in Canberra?
Transplant outdoors around late September (Sep 29–Oct 20) in Canberra, based on its local frost dates. Confidence 82%.
How long is the growing season in Canberra?
Canberra has roughly 182 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 82/100 · NOAA GHCN-Daily · 1991–2020 normals · frost dates are probabilities, not guarantees.