When to plant Leeks in Wyoming

In spring, from Apr 15 – May 15 in Casper to May 1 – 20 in Sheridan.

In fall, May 1 – June 1.

USDA's earliest safe spring and latest safe fall planting dates, matched to each place's average frost dates.

Leeks planting dates by place in Wyoming
PlaceSpringFall
CasperApr 15 – May 15Spring-planted
CheyenneApr 15 – May 15Spring-planted
CodyApr 15 – May 15Spring-planted
EvanstonMay 1 – 15May 1 – June 1
GilletteApr 15 – May 15Spring-planted
Green RiverMay 1 – 20Spring-planted
JacksonMay 1 – 15May 1 – June 1
LaramieMay 1 – 15May 1 – June 1
RivertonApr 15 – May 15Spring-planted
Rock SpringsMay 1 – 20Spring-planted
SheridanMay 1 – 20Spring-planted

Planting dates: USDA Home and Garden Bulletin No. 9 (1967), tables 4 and 5. Frost dates: NOAA U.S. Climate Normals 1991–2020. “—” means the place's frost date is outside the table. The full USDA table for leeks.