When to plant onion in Lyon
Onion is cold-hardy, so every date keys off Lyon's frost dates of Apr 15.
Step 1 · Sow
Start seeds indoors
Feb 4 – Feb 25
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Mar 25 – Apr 15
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Jun 23 – Jul 13
Picking runs until conditions turn against the crop.
Window
Days to maturity
90 – 110 d
Lyon's 193-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
APR 15
OCT 25
Common questions
When will onion be ready to harvest in Lyon?
Expect to harvest from around late June (Jun 23–Jul 13) in Lyon, based on its local frost dates. Confidence 77%.
When should I start onion seeds indoors in Lyon?
Start seeds indoors around early February (Feb 4–Feb 25) in Lyon, based on its local frost dates. Confidence 82%.
When can I transplant onion outdoors in Lyon?
Transplant outdoors around late March (Mar 25–Apr 15) in Lyon, based on its local frost dates. Confidence 86%.
How long is the growing season in Lyon?
Lyon has roughly 193 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 86/100 · NOAA GHCN-Daily · 1991–2020 normals · frost dates are probabilities, not guarantees.