When to plant onion in Dunedin
Onion is cold-hardy, so every date keys off Dunedin's frost dates of Oct 18.
Step 1 · Sow
Start seeds indoors
Aug 9 – Aug 30
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Sep 27 – Oct 18
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Dec 26 – Jan 15
Picking runs until conditions turn against the crop.
Window
Days to maturity
90 – 110 d
Dunedin's 178-day season leaves this much room.
Onion on Dunedin'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 18
APR 14
Common questions
When will onion be ready to harvest in Dunedin?
Expect to harvest from around late December (Dec 26–Jan 15) in Dunedin, based on its local frost dates. Confidence 61%.
When should I start onion seeds indoors in Dunedin?
Start seeds indoors around early August (Aug 9–Aug 30) in Dunedin, based on its local frost dates. Confidence 65%.
When can I transplant onion outdoors in Dunedin?
Transplant outdoors around late September (Sep 27–Oct 18) in Dunedin, based on its local frost dates. Confidence 68%.
How long is the growing season in Dunedin?
Dunedin has roughly 178 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 Dunedin's frost dates.
Confidence 68/100 · NASA POWER (modeled) · 1991–2020 · frost dates are probabilities, not guarantees.