When to plant tulip bulbs in Colorado

Fall planting in Denver

Sep 24–Oct 29

Across Colorado the window opens between September 17 and October 9. Find your city below; the dates follow each town's own average first fall frost.

Fall planting, Denver: Sep 24–Oct 29
Last frost, Denver: May 4

Plant from 2 weeks before to 3 weeks after the first fall frost. Plant once the soil has cooled below 60°F. Bulbs need 12–14 weeks of cold to flower in spring.

Tulip bulbs planting dates by city

Start indoorsPlant outSow outdoorsFall plantingAverage last and first frost

JanFebMarAprMayJunJulAugSepOctNovDec

DenverSep 24–Oct 29

Colorado SpringsSep 24–Oct 29

AuroraSep 24–Oct 29

Fort CollinsSep 23–Oct 28

LakewoodSep 23–Oct 28

ThorntonSep 27–Nov 1

ArvadaSep 21–Oct 26

WestminsterSep 27–Nov 1

GreeleySep 24–Oct 29

PuebloSep 25–Oct 30

CentennialSep 24–Oct 29

BoulderSep 21–Oct 26

LongmontSep 21–Oct 26

LovelandSep 17–Oct 22

BroomfieldSep 27–Nov 1

Commerce CitySep 23–Oct 28

Grand JunctionOct 9–Nov 13

LittletonSep 27–Nov 1

BrightonSep 23–Oct 28

WindsorSep 22–Oct 27

ErieSep 21–Oct 26

NorthglennSep 27–Nov 1

Security-WidefieldSep 24–Oct 29

EnglewoodSep 27–Nov 1

Pueblo WestSep 29–Nov 3

Wheat RidgeSep 21–Oct 26

LafayetteSep 27–Nov 1

FountainSep 24–Oct 29

EvansSep 24–Oct 29

JohnstownSep 17–Oct 22

All 34 cities

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

Questions

When should I plant tulip bulbs in Colorado?

In Denver, fall planting from September 24 to October 29. Across Colorado the window opens between September 17 and October 9, depending on the local last frost.

How is this date worked out?

Plant from 2 weeks before to 3 weeks after the first fall frost. Frost dates are NOAA 1991–2020 averages for the weather station nearest each city.