When to plant sunflowers in Colorado

Sunflowers
Sow outdoors in Denver
May 4–May 25

Across Colorado the window opens between April 14 and May 10. Find your city below; the dates follow each town's own average last frost.

Sow outdoors, Denver
May 4–May 25
Last sowing for a harvest
Jun 16
Last frost, Denver
May 4

Sow outdoors up to 3 weeks after the last frost. Sow every two weeks until midsummer for flowers through fall.

Sunflowers planting dates by city

Start indoorsPlant outSow outdoorsFall plantingAverage last and first frost
JanFebMarAprMayJunJulAugSepOctNovDec
DenverMay 4–May 25
Colorado SpringsMay 3–May 24
AuroraMay 7–May 28
Fort CollinsMay 2–May 23
LakewoodMay 3–May 24
ThorntonMay 2–May 23
ArvadaMay 5–May 26
WestminsterMay 2–May 23
GreeleyMay 2–May 23
PuebloApr 30–May 21
CentennialMay 5–May 26
BoulderMay 6–May 27
LongmontMay 7–May 28
LovelandMay 10–May 31
BroomfieldMay 2–May 23
Commerce CityMay 3–May 24
Grand JunctionApr 14–May 5
LittletonMay 2–May 23
BrightonMay 3–May 24
WindsorMay 3–May 24
ErieMay 7–May 28
NorthglennMay 2–May 23
Security-WidefieldMay 3–May 24
EnglewoodMay 2–May 23
Pueblo WestApr 26–May 17
Wheat RidgeMay 5–May 26
LafayetteMay 2–May 23
FountainMay 3–May 24
EvansMay 2–May 23
JohnstownMay 10–May 31
All 34 cities
CitySow outdoorsLast frost
DenverMay 4 to May 25May 4
Colorado SpringsMay 3 to May 24May 3
AuroraMay 7 to May 28May 7
Fort CollinsMay 2 to May 23May 2
LakewoodMay 3 to May 24May 3
ThorntonMay 2 to May 23May 2
ArvadaMay 5 to May 26May 5
WestminsterMay 2 to May 23May 2
GreeleyMay 2 to May 23May 2
PuebloApr 30 to May 21Apr 30
CentennialMay 5 to May 26May 5
BoulderMay 6 to May 27May 6
LongmontMay 7 to May 28May 7
LovelandMay 10 to May 31May 10
BroomfieldMay 2 to May 23May 2
Commerce CityMay 3 to May 24May 3
Grand JunctionApr 14 to May 5Apr 14
LittletonMay 2 to May 23May 2
BrightonMay 3 to May 24May 3
WindsorMay 3 to May 24May 3
ErieMay 7 to May 28May 7
NorthglennMay 2 to May 23May 2
Security-WidefieldMay 3 to May 24May 3
EnglewoodMay 2 to May 23May 2
Pueblo WestApr 26 to May 17Apr 26
Wheat RidgeMay 5 to May 26May 5
LafayetteMay 2 to May 23May 2
FountainMay 3 to May 24May 3
EvansMay 2 to May 23May 2
JohnstownMay 10 to May 31May 10
Four Square MileMay 7 to May 28May 7
MontroseApr 28 to May 19Apr 28
LouisvilleMay 6 to May 27May 6
FirestoneMay 7 to May 28May 7

Questions

When should I plant sunflowers in Colorado?

In Denver, sow outdoors from May 4 to May 25. Across Colorado the window opens between April 14 and May 10, depending on the local last frost.

How is this date worked out?

Sow outdoors up to 3 weeks after the last frost. Frost dates are NOAA 1991–2020 averages for the weather station nearest each city.

More for Colorado

Sunflowers in other states

Frost dates for every city in Colorado