FrostCal

When to Plant Zinnias in Wyoming

In a typical Wyoming location, start seeds indoors Apr 19 – Apr 26, then sow outdoors May 24 – Jun 7, then transplant outdoors May 24 – May 31. Across the state, the outdoor planting window starts as early as May 11 in Worland and as late as Jun 19 in Evanston. 1 city in Wyoming is essentially frost-free and can plant on a year-round schedule.

Method Direct sow
Days to maturity 60–70 days

Frost-tender; direct sow 1-3 weeks after last frost, or start indoors 3-4 weeks early for earlier blooms.

Zinnias Planting Dates by City

CityStart indoorsDirect sowTransplant
CheyenneApr 16 – Apr 23May 21 – Jun 4May 21 – May 28
CasperApr 12 – Apr 19May 17 – May 31May 17 – May 24
GilletteApr 17 – Apr 24May 22 – Jun 5May 22 – May 29
LaramieMay 10 – May 17Jun 14 – Jun 28Jun 14 – Jun 21
Rock SpringsApr 26 – May 3May 31 – Jun 14May 31 – Jun 7
SheridanApr 23 – Apr 30May 28 – Jun 11May 28 – Jun 4
Green RiverApr 26 – May 3May 31 – Jun 14May 31 – Jun 7
EvanstonMay 15 – May 22Jun 19 – Jul 3Jun 19 – Jun 26
RivertonApr 14 – Apr 21May 19 – Jun 2May 19 – May 26
JacksonFrost-free: year-round planting
CodyApr 14 – Apr 21May 19 – Jun 2May 19 – May 26
RawlinsApr 19 – Apr 26May 24 – Jun 7May 24 – May 31
LanderApr 20 – Apr 27May 25 – Jun 8May 25 – Jun 1
TorringtonApr 13 – Apr 20May 18 – Jun 1May 18 – May 25
DouglasApr 21 – Apr 28May 26 – Jun 9May 26 – Jun 2
PowellApr 21 – Apr 28May 26 – Jun 9May 26 – Jun 2
RanchettesApr 14 – Apr 21May 19 – Jun 2May 19 – May 26
WorlandApr 6 – Apr 13May 11 – May 25May 11 – May 18
BuffaloApr 26 – May 3May 31 – Jun 14May 31 – Jun 7
South GreeleyApr 16 – Apr 23May 21 – Jun 4May 21 – May 28

Showing the 20 most populous of 20 Wyoming cities. Dates are estimates from each city's NOAA frost normals and university extension timing guidelines. See all Wyoming cities.

Frequently Asked Questions

When should I plant zinnias in Wyoming?

In a typical Wyoming location, start seeds indoors Apr 19 – Apr 26, then sow outdoors May 24 – Jun 7, then transplant outdoors May 24 – May 31. Across the state, the outdoor planting window starts as early as May 11 in Worland and as late as Jun 19 in Evanston. 1 city in Wyoming is essentially frost-free and can plant on a year-round schedule.

When is the last frost in Wyoming?

The average last spring frost in Wyoming ranges from May 4 in Worland to June 12 in Evanston, based on NOAA 1991–2020 climate normals.

How long do zinnias take to grow?

Zinnias typically take 60–70 days from planting to harvest. Frost-tender; direct sow 1-3 weeks after last frost, or start indoors 3-4 weeks early for earlier blooms.

Other Crops in Wyoming

When to plant zinnias in other states

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