When to plant onion in Houston
Onion is cold-hardy, so every date keys off Houston's frost dates of Jan 26.
Step 1 · Sow
Start seeds indoors
Nov 17 – Dec 8
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Dec 25 – Jan 15
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Mar 25 – Apr 14
Picking runs until conditions turn against the crop.
Window
Days to maturity
90 – 110 d
Houston's 317-day season leaves this much room.
Onion on Houston'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
JAN 26
DEC 9
Common questions
When will onion be ready to harvest in Houston?
Expect to harvest from around late March (Mar 25–Apr 14) in Houston, based on its local frost dates. Confidence 76%.
When should I start onion seeds indoors in Houston?
Start seeds indoors around mid November (Nov 17–Dec 8) in Houston, based on its local frost dates. Confidence 80%.
When can I transplant onion outdoors in Houston?
Transplant outdoors around late December (Dec 25–Jan 15) in Houston, based on its local frost dates. Confidence 81%.
How long is the growing season in Houston?
Houston has roughly 317 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 Houston's frost dates.
Confidence 84/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.