When to plant tomatoes in Colorado

Plant out in Denver

May 11–May 25

Across Colorado the window opens between April 21 and May 17. Find your city below; the dates follow each town's own average last frost.

Start indoors, Denver: Mar 9–Mar 23
Plant out, Denver: May 11–May 25
Last sowing for a harvest: Jul 1
Last frost, Denver: May 4

Start seeds indoors 6–8 weeks before the last frost; plant out 1–3 weeks after the last frost. Wait for nights that stay above 50°F. A cold snap after transplanting stalls tomatoes for weeks.

Tomatoes planting dates by city

Start indoorsPlant outSow outdoorsFall plantingAverage last and first frost

JanFebMarAprMayJunJulAugSepOctNovDec

DenverMay 11–May 25

Colorado SpringsMay 10–May 24

AuroraMay 14–May 28

Fort CollinsMay 9–May 23

LakewoodMay 10–May 24

ThorntonMay 9–May 23

ArvadaMay 12–May 26

WestminsterMay 9–May 23

GreeleyMay 9–May 23

PuebloMay 7–May 21

CentennialMay 12–May 26

BoulderMay 13–May 27

LongmontMay 14–May 28

LovelandMay 17–May 31

BroomfieldMay 9–May 23

Commerce CityMay 10–May 24

Grand JunctionApr 21–May 5

LittletonMay 9–May 23

BrightonMay 10–May 24

WindsorMay 10–May 24

ErieMay 14–May 28

NorthglennMay 9–May 23

Security-WidefieldMay 10–May 24

EnglewoodMay 9–May 23

Pueblo WestMay 3–May 17

Wheat RidgeMay 12–May 26

LafayetteMay 9–May 23

FountainMay 10–May 24

EvansMay 9–May 23

JohnstownMay 17–May 31

All 34 cities

City	Start indoors	Plant out	Last frost
Denver	Mar 9 to Mar 23	May 11 to May 25	May 4
Colorado Springs	Mar 8 to Mar 22	May 10 to May 24	May 3
Aurora	Mar 12 to Mar 26	May 14 to May 28	May 7
Fort Collins	Mar 7 to Mar 21	May 9 to May 23	May 2
Lakewood	Mar 8 to Mar 22	May 10 to May 24	May 3
Thornton	Mar 7 to Mar 21	May 9 to May 23	May 2
Arvada	Mar 10 to Mar 24	May 12 to May 26	May 5
Westminster	Mar 7 to Mar 21	May 9 to May 23	May 2
Greeley	Mar 7 to Mar 21	May 9 to May 23	May 2
Pueblo	Mar 5 to Mar 19	May 7 to May 21	Apr 30
Centennial	Mar 10 to Mar 24	May 12 to May 26	May 5
Boulder	Mar 11 to Mar 25	May 13 to May 27	May 6
Longmont	Mar 12 to Mar 26	May 14 to May 28	May 7
Loveland	Mar 15 to Mar 29	May 17 to May 31	May 10
Broomfield	Mar 7 to Mar 21	May 9 to May 23	May 2
Commerce City	Mar 8 to Mar 22	May 10 to May 24	May 3
Grand Junction	Feb 17 to Mar 3	Apr 21 to May 5	Apr 14
Littleton	Mar 7 to Mar 21	May 9 to May 23	May 2
Brighton	Mar 8 to Mar 22	May 10 to May 24	May 3
Windsor	Mar 8 to Mar 22	May 10 to May 24	May 3
Erie	Mar 12 to Mar 26	May 14 to May 28	May 7
Northglenn	Mar 7 to Mar 21	May 9 to May 23	May 2
Security-Widefield	Mar 8 to Mar 22	May 10 to May 24	May 3
Englewood	Mar 7 to Mar 21	May 9 to May 23	May 2
Pueblo West	Mar 1 to Mar 15	May 3 to May 17	Apr 26
Wheat Ridge	Mar 10 to Mar 24	May 12 to May 26	May 5
Lafayette	Mar 7 to Mar 21	May 9 to May 23	May 2
Fountain	Mar 8 to Mar 22	May 10 to May 24	May 3
Evans	Mar 7 to Mar 21	May 9 to May 23	May 2
Johnstown	Mar 15 to Mar 29	May 17 to May 31	May 10
Four Square Mile	Mar 12 to Mar 26	May 14 to May 28	May 7
Montrose	Mar 3 to Mar 17	May 5 to May 19	Apr 28
Louisville	Mar 11 to Mar 25	May 13 to May 27	May 6
Firestone	Mar 12 to Mar 26	May 14 to May 28	May 7

Questions

When should I plant tomatoes in Colorado?

In Denver, plant out from May 11 to May 25. Across Colorado the window opens between April 21 and May 17, depending on the local last frost.

How is this date worked out?

Start seeds indoors 6–8 weeks before the last frost; plant out 1–3 weeks after the last frost. Frost dates are NOAA 1991–2020 averages for the weather station nearest each city.

More for Colorado

Tomatoes in other states

Frost dates for every city in Colorado