When to plant onion in Lyon
Onion is cold-hardy, so every date keys off Lyon's frost dates of Mar 26.
Step 1 · Sow
Start seeds indoors
Jan 15 – Feb 5
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Mar 26 – Apr 16
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Jun 24 – Jul 14
Picking runs until conditions turn against the crop.
Window
Days to maturity
90 – 110 d
Lyon's 232-day season leaves this much room.
Onion on Lyon'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
MAR 26
NOV 16
Common questions
When will onion be ready to harvest in Lyon?
Expect to harvest from around late June (Jun 24–Jul 14) in Lyon, based on its local frost dates. Confidence 78%.
When should I start onion seeds indoors in Lyon?
Start seeds indoors around mid January (Jan 15–Feb 5) in Lyon, based on its local frost dates. Confidence 83%.
When can I transplant onion outdoors in Lyon?
Transplant outdoors around late March (Mar 26–Apr 16) in Lyon, based on its local frost dates. Confidence 84%.
How long is the growing season in Lyon?
Lyon has roughly 232 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 Lyon's frost dates.
Confidence 87/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.