When to plant onion in Wellington
Onion is cold-hardy, so every date keys off Wellington's frost dates of Sep 1.
Step 1 · Sow
Start seeds indoors
Jun 23 – Jul 14
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Aug 11 – Sep 1
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Nov 9 – Nov 29
Picking runs until conditions turn against the crop.
Window
Days to maturity
90 – 110 d
Wellington's 273-day season leaves this much room.
Onion on Wellington'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
SEP 1
JUN 1
Common questions
When will onion be ready to harvest in Wellington?
Expect to harvest from around early November (Nov 9–Nov 29) in Wellington, based on its local frost dates. Confidence 72%.
When should I start onion seeds indoors in Wellington?
Start seeds indoors around late June (Jun 23–Jul 14) in Wellington, based on its local frost dates. Confidence 76%.
When can I transplant onion outdoors in Wellington?
Transplant outdoors around mid August (Aug 11–Sep 1) in Wellington, based on its local frost dates. Confidence 80%.
How long is the growing season in Wellington?
Wellington has roughly 273 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 Wellington's frost dates.
Confidence 80/100 · NOAA GHCN-Daily · 1991–2020 normals · frost dates are probabilities, not guarantees.