When to plant lettuce in Colorado

Plant out in Denver

Apr 20–May 11

Across Colorado the window opens between March 31 and April 26. Find your city below; the dates follow each town's own average last frost.

Start indoors, Denver: Mar 9–Mar 23
Plant out, Denver: Apr 20–May 11
Sow outdoors, Denver: Apr 6–May 11
Fall planting, Denver: Aug 13–Aug 27
Last frost, Denver: May 4

Start seeds indoors 6–8 weeks before the last frost; plant out from 2 weeks before to 1 weeks after the last frost; sow outdoors from 4 weeks before to 1 weeks after the last frost; sow again for fall 6–8 weeks before the first frost. Lettuce bolts in heat. Sow small batches every two weeks in spring and again in late summer.

Lettuce planting dates by city

Start indoorsPlant outSow outdoorsFall plantingAverage last and first frost

JanFebMarAprMayJunJulAugSepOctNovDec

DenverApr 20–May 11

Colorado SpringsApr 19–May 10

AuroraApr 23–May 14

Fort CollinsApr 18–May 9

LakewoodApr 19–May 10

ThorntonApr 18–May 9

ArvadaApr 21–May 12

WestminsterApr 18–May 9

GreeleyApr 18–May 9

PuebloApr 16–May 7

CentennialApr 21–May 12

BoulderApr 22–May 13

LongmontApr 23–May 14

LovelandApr 26–May 17

BroomfieldApr 18–May 9

Commerce CityApr 19–May 10

Grand JunctionMar 31–Apr 21

LittletonApr 18–May 9

BrightonApr 19–May 10

WindsorApr 19–May 10

ErieApr 23–May 14

NorthglennApr 18–May 9

Security-WidefieldApr 19–May 10

EnglewoodApr 18–May 9

Pueblo WestApr 12–May 3

Wheat RidgeApr 21–May 12

LafayetteApr 18–May 9

FountainApr 19–May 10

EvansApr 18–May 9

JohnstownApr 26–May 17

All 34 cities

City	Start indoors	Plant out	Sow outdoors	Fall planting	Last frost
Denver	Mar 9 to Mar 23	Apr 20 to May 11	Apr 6 to May 11	Aug 13 to Aug 27	May 4
Colorado Springs	Mar 8 to Mar 22	Apr 19 to May 10	Apr 5 to May 10	Aug 13 to Aug 27	May 3
Aurora	Mar 12 to Mar 26	Apr 23 to May 14	Apr 9 to May 14	Aug 13 to Aug 27	May 7
Fort Collins	Mar 7 to Mar 21	Apr 18 to May 9	Apr 4 to May 9	Aug 12 to Aug 26	May 2
Lakewood	Mar 8 to Mar 22	Apr 19 to May 10	Apr 5 to May 10	Aug 12 to Aug 26	May 3
Thornton	Mar 7 to Mar 21	Apr 18 to May 9	Apr 4 to May 9	Aug 16 to Aug 30	May 2
Arvada	Mar 10 to Mar 24	Apr 21 to May 12	Apr 7 to May 12	Aug 10 to Aug 24	May 5
Westminster	Mar 7 to Mar 21	Apr 18 to May 9	Apr 4 to May 9	Aug 16 to Aug 30	May 2
Greeley	Mar 7 to Mar 21	Apr 18 to May 9	Apr 4 to May 9	Aug 13 to Aug 27	May 2
Pueblo	Mar 5 to Mar 19	Apr 16 to May 7	Apr 2 to May 7	Aug 14 to Aug 28	Apr 30
Centennial	Mar 10 to Mar 24	Apr 21 to May 12	Apr 7 to May 12	Aug 13 to Aug 27	May 5
Boulder	Mar 11 to Mar 25	Apr 22 to May 13	Apr 8 to May 13	Aug 10 to Aug 24	May 6
Longmont	Mar 12 to Mar 26	Apr 23 to May 14	Apr 9 to May 14	Aug 10 to Aug 24	May 7
Loveland	Mar 15 to Mar 29	Apr 26 to May 17	Apr 12 to May 17	May 10
Broomfield	Mar 7 to Mar 21	Apr 18 to May 9	Apr 4 to May 9	Aug 16 to Aug 30	May 2
Commerce City	Mar 8 to Mar 22	Apr 19 to May 10	Apr 5 to May 10	Aug 12 to Aug 26	May 3
Grand Junction	Feb 17 to Mar 3	Mar 31 to Apr 21	Mar 17 to Apr 21	Aug 28 to Sep 11	Apr 14
Littleton	Mar 7 to Mar 21	Apr 18 to May 9	Apr 4 to May 9	Aug 16 to Aug 30	May 2
Brighton	Mar 8 to Mar 22	Apr 19 to May 10	Apr 5 to May 10	Aug 12 to Aug 26	May 3
Windsor	Mar 8 to Mar 22	Apr 19 to May 10	Apr 5 to May 10	Aug 11 to Aug 25	May 3
Erie	Mar 12 to Mar 26	Apr 23 to May 14	Apr 9 to May 14	Aug 10 to Aug 24	May 7
Northglenn	Mar 7 to Mar 21	Apr 18 to May 9	Apr 4 to May 9	Aug 16 to Aug 30	May 2
Security-Widefield	Mar 8 to Mar 22	Apr 19 to May 10	Apr 5 to May 10	Aug 13 to Aug 27	May 3
Englewood	Mar 7 to Mar 21	Apr 18 to May 9	Apr 4 to May 9	Aug 16 to Aug 30	May 2
Pueblo West	Mar 1 to Mar 15	Apr 12 to May 3	Mar 29 to May 3	Aug 18 to Sep 1	Apr 26
Wheat Ridge	Mar 10 to Mar 24	Apr 21 to May 12	Apr 7 to May 12	Aug 10 to Aug 24	May 5
Lafayette	Mar 7 to Mar 21	Apr 18 to May 9	Apr 4 to May 9	Aug 16 to Aug 30	May 2
Fountain	Mar 8 to Mar 22	Apr 19 to May 10	Apr 5 to May 10	Aug 13 to Aug 27	May 3
Evans	Mar 7 to Mar 21	Apr 18 to May 9	Apr 4 to May 9	Aug 13 to Aug 27	May 2
Johnstown	Mar 15 to Mar 29	Apr 26 to May 17	Apr 12 to May 17	May 10
Four Square Mile	Mar 12 to Mar 26	Apr 23 to May 14	Apr 9 to May 14	Aug 13 to Aug 27	May 7
Montrose	Mar 3 to Mar 17	Apr 14 to May 5	Mar 31 to May 5	Aug 19 to Sep 2	Apr 28
Louisville	Mar 11 to Mar 25	Apr 22 to May 13	Apr 8 to May 13	Aug 10 to Aug 24	May 6
Firestone	Mar 12 to Mar 26	Apr 23 to May 14	Apr 9 to May 14	Aug 10 to Aug 24	May 7

Questions

When should I plant lettuce in Colorado?

In Denver, plant out from April 20 to May 11. Across Colorado the window opens between March 31 and April 26, depending on the local last frost.

How is this date worked out?

Start seeds indoors 6–8 weeks before the last frost; plant out from 2 weeks before to 1 weeks after the last frost; sow outdoors from 4 weeks before to 1 weeks after the last frost; sow again for fall 6–8 weeks before the first frost. Frost dates are NOAA 1991–2020 averages for the weather station nearest each city.

More for Colorado

Lettuce in other states

Frost dates for every city in Colorado