When to plant onion in Grand Rapids
Onion is cold-hardy, so every date keys off Grand Rapids's frost dates of Apr 30.
Step 1 · Sow
Start seeds indoors
Feb 19 – Mar 12
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
Grand Rapids's 166-day season leaves this much room.
Onion on Grand Rapids'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 30
OCT 16
Common questions
When will onion be ready to harvest in Grand Rapids?
Expect to harvest from around late July (Jul 28–Aug 17) in Grand Rapids, based on its local frost dates. Confidence 78%.
When should I start onion seeds indoors in Grand Rapids?
Start seeds indoors around mid February (Feb 19–Mar 12) in Grand Rapids, based on its local frost dates. Confidence 83%.
When can I transplant onion outdoors in Grand Rapids?
Transplant outdoors around late April (Apr 29–May 20) in Grand Rapids, based on its local frost dates. Confidence 84%.
How long is the growing season in Grand Rapids?
Grand Rapids has roughly 166 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 Grand Rapids's frost dates.
Confidence 87/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.