When to plant tomato in Denver
Tomato is frost-tender, so every date keys off Denver's last spring frost of May 4.
Step 1 · Sow
Start seeds indoors
Apr 9 – Apr 30
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Jun 1 – Jun 22
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Jul 31 – Aug 25
Picking runs until conditions turn against the crop.
Window
Days to maturity
60 – 85 d
Denver's 157-day season leaves this much room.
Tomato on Denver'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
MAY 4
OCT 10
Common questions
When will tomato be ready to harvest in Denver?
Expect to harvest from around late July (Jul 31–Aug 25) in Denver, based on its local frost dates. Confidence 76%.
When should I start tomato seeds indoors in Denver?
Start seeds indoors around early April (Apr 9–Apr 30) in Denver, based on its local frost dates. Confidence 81%.
When can I transplant tomato outdoors in Denver?
Transplant outdoors around early June (Jun 1–Jun 22) in Denver, based on its local frost dates. Confidence 82%.
How long is the growing season in Denver?
Denver has roughly 157 frost-free days, which is enough time to grow tomato to maturity outdoors.
The rule of thumb
Sow tomato 6–8 weeks before your last spring frost; plant out 2–3 weeks after it. Every date on this page is derived from that rule and Denver's frost dates.
Confidence 85/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.