When to plant onion in Saint Paul
Onion is cold-hardy, so every date keys off Saint Paul's frost dates of Apr 22.
Step 1 · Sow
Start seeds indoors
Feb 11 – Mar 4
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Apr 29 – May 20
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Jul 28 – Aug 17
Picking runs until conditions turn against the crop.
Window
Days to maturity
90 – 110 d
Saint Paul's 174-day season leaves this much room.
Onion on Saint Paul'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 22
OCT 12
Common questions
When will onion be ready to harvest in Saint Paul?
Expect to harvest from around late July (Jul 28–Aug 17) in Saint Paul, based on its local frost dates. Confidence 76%.
When should I start onion seeds indoors in Saint Paul?
Start seeds indoors around mid February (Feb 11–Mar 4) in Saint Paul, based on its local frost dates. Confidence 80%.
When can I transplant onion outdoors in Saint Paul?
Transplant outdoors around late April (Apr 29–May 20) in Saint Paul, based on its local frost dates. Confidence 81%.
How long is the growing season in Saint Paul?
Saint Paul has roughly 174 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 Saint Paul's frost dates.
Confidence 84/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.