When to plant sunflowers in Idaho

Sow outdoors in Boise City

Apr 24–May 15

Across Idaho the window opens between April 6 and May 12. Find your city below; the dates follow each town's own average last frost.

Sow outdoors up to 3 weeks after the last frost. Sow every two weeks until midsummer for flowers through fall.

Sunflowers planting dates by city

Start indoorsPlant outSow outdoorsFall plantingAverage last and first frost

JanFebMarAprMayJunJulAugSepOctNovDec

Boise CityApr 24–May 15

MeridianApr 24–May 15

NampaApr 29–May 20

CaldwellApr 29–May 20

Idaho FallsMay 9–May 30

PocatelloMay 2–May 23

Coeur d'AleneApr 22–May 13

Twin FallsApr 30–May 21

Post FallsApr 22–May 13

RexburgMay 12–Jun 2

LewistonApr 6–Apr 27

EagleApr 29–May 20

KunaApr 24–May 15

StarApr 29–May 20

AmmonMay 9–May 30

When should I plant sunflowers in Idaho?

In Boise City, sow outdoors from April 24 to May 15. Across Idaho the window opens between April 6 and May 12, depending on the local last frost.

How is this date worked out?

Sow outdoors up to 3 weeks after the last frost. Frost dates are NOAA 1991–2020 averages for the weather station nearest each city.