FrostCal

When to Plant Thyme in Idaho

In a typical Idaho location, start seeds indoors Mar 5 – Mar 19, then transplant outdoors Apr 30 – May 7. Across the state, the outdoor planting window starts as early as Apr 6 in Lewiston and as late as May 17 in Eagle. 2 cities in Idaho are essentially frost-free and can plant on a year-round schedule.

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
BoiseFeb 27 – Mar 13Apr 24 – May 1
MeridianFeb 27 – Mar 13Apr 24 – May 1
NampaMar 4 – Mar 18Apr 29 – May 6
Idaho FallsMar 14 – Mar 28May 9 – May 16
PocatelloMar 7 – Mar 21May 2 – May 9
CaldwellFeb 26 – Mar 12Apr 23 – Apr 30
Coeur d'AleneFeb 25 – Mar 11Apr 22 – Apr 29
Twin FallsMar 5 – Mar 19Apr 30 – May 7
LewistonFeb 9 – Feb 23Apr 6 – Apr 13
Lewiston OrchardsFeb 9 – Feb 23Apr 6 – Apr 13
Post FallsFeb 25 – Mar 11Apr 22 – Apr 29
RexburgMar 20 – Apr 3May 15 – May 22
MoscowFrost-free: year-round planting
EagleMar 22 – Apr 5May 17 – May 24
CondaFrost-free: year-round planting
KunaFeb 27 – Mar 13Apr 24 – May 1
AmmonMar 14 – Mar 28May 9 – May 16
ChubbuckMar 7 – Mar 21May 2 – May 9
HaydenFeb 25 – Mar 11Apr 22 – Apr 29
Mountain HomeMar 7 – Mar 21May 2 – May 9
BlackfootMar 10 – Mar 24May 5 – May 12
Garden CityFeb 27 – Mar 13Apr 24 – May 1
JeromeMar 7 – Mar 21May 2 – May 9
BurleyMar 12 – Mar 26May 7 – May 14

Showing the 24 most populous of 24 Idaho cities. Dates are estimates from each city's NOAA frost normals and university extension timing guidelines. See all Idaho cities.

Frequently Asked Questions

When should I plant thyme in Idaho?

In a typical Idaho location, start seeds indoors Mar 5 – Mar 19, then transplant outdoors Apr 30 – May 7. Across the state, the outdoor planting window starts as early as Apr 6 in Lewiston and as late as May 17 in Eagle. 2 cities in Idaho are essentially frost-free and can plant on a year-round schedule.

When is the last frost in Idaho?

The average last spring frost in Idaho ranges from April 6 in Lewiston to May 17 in Eagle, 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 Idaho

When to plant thyme in other states

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