FrostCal

When to Plant Thyme in Colorado

In a typical Colorado location, start seeds indoors Mar 8 – Mar 22, then transplant outdoors May 3 – May 10. Across the state, the outdoor planting window starts as early as Apr 14 in Grand Junction and as late as Jun 21 in Edwards.

Method Start indoors, then transplant
Days to maturity 85–95 days

Perennial herb, slow from seed; start indoors 6-8 weeks before last frost, transplant around/after last frost.

Thyme Planting Dates by City

CityStart indoorsTransplant
DenverMar 5 – Mar 19Apr 30 – May 7
Colorado SpringsMar 8 – Mar 22May 3 – May 10
AuroraMar 9 – Mar 23May 4 – May 11
Fort CollinsMar 7 – Mar 21May 2 – May 9
LakewoodMar 8 – Mar 22May 3 – May 10
ThorntonMar 7 – Mar 21May 2 – May 9
WestminsterMar 7 – Mar 21May 2 – May 9
ArvadaMar 10 – Mar 24May 5 – May 12
CentennialMar 10 – Mar 24May 5 – May 12
PuebloMar 5 – Mar 19Apr 30 – May 7
GreeleyMar 7 – Mar 21May 2 – May 9
BoulderMar 11 – Mar 25May 6 – May 13
Highlands RanchMar 10 – Mar 24May 5 – May 12
LongmontMar 12 – Mar 26May 7 – May 14
LovelandMar 15 – Mar 29May 10 – May 17
BroomfieldMar 7 – Mar 21May 2 – May 9
Grand JunctionFeb 17 – Mar 3Apr 14 – Apr 21
Castle RockMar 14 – Mar 28May 9 – May 16
Commerce CityMar 9 – Mar 23May 4 – May 11
ParkerMar 14 – Mar 28May 9 – May 16
LittletonMar 7 – Mar 21May 2 – May 9
NorthglennMar 7 – Mar 21May 2 – May 9
BrightonMar 8 – Mar 22May 3 – May 10
Dakota RidgeMar 7 – Mar 21May 2 – May 9
EnglewoodMar 7 – Mar 21May 2 – May 9
Security-WidefieldMar 8 – Mar 22May 3 – May 10
WindsorMar 8 – Mar 22May 3 – May 10
Ken CarylMar 7 – Mar 21May 2 – May 9
Wheat RidgeMar 10 – Mar 24May 5 – May 12
Pueblo WestMar 1 – Mar 15Apr 26 – May 3

Showing the 30 most populous of 65 Colorado cities. Dates are estimates from each city's NOAA frost normals and university extension timing guidelines. See all Colorado cities.

Frequently Asked Questions

When should I plant thyme in Colorado?

In a typical Colorado location, start seeds indoors Mar 8 – Mar 22, then transplant outdoors May 3 – May 10. Across the state, the outdoor planting window starts as early as Apr 14 in Grand Junction and as late as Jun 21 in Edwards.

When is the last frost in Colorado?

The average last spring frost in Colorado ranges from April 14 in Grand Junction to June 21 in Edwards, based on NOAA 1991–2020 climate normals.

How long do thyme take to grow?

Thyme typically take 85–95 days from planting to harvest. Perennial herb, slow from seed; start indoors 6-8 weeks before last frost, transplant around/after last frost.

Other Crops in Colorado

When to plant thyme in other states

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