When to plant onion in Marseille
Onion is cold-hardy, so every date keys off Marseille's frost dates of Feb 22.
Step 1 · Sow
Start seeds indoors
Dec 14 – Jan 4
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Mar 12 – Apr 2
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Jun 10 – Jun 30
Picking runs until conditions turn against the crop.
Window
Days to maturity
90 – 110 d
Marseille's 284-day season leaves this much room.
Onion on Marseille'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
FEB 22
DEC 3
Common questions
When will onion be ready to harvest in Marseille?
Expect to harvest from around early June (Jun 10–Jun 30) in Marseille, based on its local frost dates. Confidence 79%.
When should I start onion seeds indoors in Marseille?
Start seeds indoors around mid December (Dec 14–Jan 4) in Marseille, based on its local frost dates. Confidence 84%.
When can I transplant onion outdoors in Marseille?
Transplant outdoors around mid March (Mar 12–Apr 2) in Marseille, based on its local frost dates. Confidence 85%.
How long is the growing season in Marseille?
Marseille has roughly 284 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 Marseille's frost dates.
Confidence 88/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.