When to plant onion in Fukuoka
Onion is cold-hardy, so every date keys off Fukuoka's frost dates of Mar 15.
Step 1 · Sow
Start seeds indoors
Jan 4 – Jan 25
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Feb 22 – Mar 15
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
May 23 – Jun 12
Picking runs until conditions turn against the crop.
Window
Days to maturity
90 – 110 d
Fukuoka's 268-day season leaves this much room.
Onion on Fukuoka'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
MAR 15
DEC 8
Common questions
When will onion be ready to harvest in Fukuoka?
Expect to harvest from around late May (May 23–Jun 12) in Fukuoka, based on its local frost dates. Confidence 65%.
When should I start onion seeds indoors in Fukuoka?
Start seeds indoors around early January (Jan 4–Jan 25) in Fukuoka, based on its local frost dates. Confidence 68%.
When can I transplant onion outdoors in Fukuoka?
Transplant outdoors around late February (Feb 22–Mar 15) in Fukuoka, based on its local frost dates. Confidence 72%.
How long is the growing season in Fukuoka?
Fukuoka has roughly 268 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 Fukuoka's frost dates.
Confidence 72/100 · NASA POWER (modeled) · 1991–2020 · frost dates are probabilities, not guarantees.