When to plant onion in Montgomery
Onion is cold-hardy, so every date keys off Montgomery's frost dates of Mar 12.
Step 1 · Sow
Start seeds indoors
Jan 1 – Jan 22
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Feb 19 – Mar 12
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
May 20 – Jun 9
Picking runs until conditions turn against the crop.
Window
Days to maturity
90 – 110 d
Montgomery's 240-day season leaves this much room.
Onion on Montgomery'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
MAR 12
NOV 9
Common questions
When will onion be ready to harvest in Montgomery?
Expect to harvest from around mid May (May 20–Jun 9) in Montgomery, based on its local frost dates. Confidence 80%.
When should I start onion seeds indoors in Montgomery?
Start seeds indoors around early January (Jan 1–Jan 22) in Montgomery, based on its local frost dates. Confidence 85%.
When can I transplant onion outdoors in Montgomery?
Transplant outdoors around mid February (Feb 19–Mar 12) in Montgomery, based on its local frost dates. Confidence 89%.
How long is the growing season in Montgomery?
Montgomery has roughly 240 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 Montgomery's frost dates.
Confidence 89/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.