When to plant onion in Paris
Onion is cold-hardy, so every date keys off Paris's frost dates of Apr 3.
Step 1 · Sow
Start seeds indoors
Jan 23 – Feb 13
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Apr 11 – May 2
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Jul 10 – Jul 30
Picking runs until conditions turn against the crop.
Window
Days to maturity
90 – 110 d
Paris's 221-day season leaves this much room.
Onion on Paris'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
FROST
APR 3
NOV 11
Common questions
When will onion be ready to harvest in Paris?
Expect to harvest from around early July (Jul 10–Jul 30) in Paris, based on its local frost dates. Confidence 78%.
When should I start onion seeds indoors in Paris?
Start seeds indoors around late January (Jan 23–Feb 13) in Paris, based on its local frost dates. Confidence 83%.
When can I transplant onion outdoors in Paris?
Transplant outdoors around mid April (Apr 11–May 2) in Paris, based on its local frost dates. Confidence 84%.
How long is the growing season in Paris?
Paris has roughly 221 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 Paris's frost dates.
Confidence 87/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.