When to plant onion in Plano
Onion is cold-hardy, so every date keys off Plano's frost dates of Mar 13.
Step 1 · Sow
Start seeds indoors
Jan 2 – Jan 23
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Feb 25 – Mar 18
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
May 26 – Jun 15
Picking runs until conditions turn against the crop.
Window
Days to maturity
90 – 110 d
Plano's 250-day season leaves this much room.
Onion on Plano'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 13
NOV 23
Common questions
When will onion be ready to harvest in Plano?
Expect to harvest from around late May (May 26–Jun 15) in Plano, based on its local frost dates. Confidence 74%.
When should I start onion seeds indoors in Plano?
Start seeds indoors around early January (Jan 2–Jan 23) in Plano, based on its local frost dates. Confidence 78%.
When can I transplant onion outdoors in Plano?
Transplant outdoors around late February (Feb 25–Mar 18) in Plano, based on its local frost dates. Confidence 80%.
How long is the growing season in Plano?
Plano has roughly 250 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 Plano's frost dates.
Confidence 82/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.