FrostCal

When to Plant Cosmos in Utah

In a typical Utah location, start seeds indoors Mar 27 – Apr 3, then sow outdoors May 1 – May 15, then transplant outdoors May 1 – May 8. Across the state, the outdoor planting window starts as early as Mar 21 in Saint George and as late as Jun 11 in Heber City.

Method Direct sow
Days to maturity 60–90 days

Easy from direct seed 1-3 weeks after last frost; can also start indoors 3-4 weeks early.

Cosmos Planting Dates by City

CityStart indoorsDirect sowTransplant
Salt Lake CityMar 3 – Mar 10Apr 7 – Apr 21Apr 7 – Apr 14
West Valley CityMar 11 – Mar 18Apr 15 – Apr 29Apr 15 – Apr 22
ProvoMar 21 – Mar 28Apr 25 – May 9Apr 25 – May 2
West JordanApr 1 – Apr 8May 6 – May 20May 6 – May 13
OremMar 22 – Mar 29Apr 26 – May 10Apr 26 – May 3
SandyApr 1 – Apr 8May 6 – May 20May 6 – May 13
OgdenMar 24 – Mar 31Apr 28 – May 12Apr 28 – May 5
LaytonMar 22 – Mar 29Apr 26 – May 10Apr 26 – May 3
Saint GeorgeFeb 14 – Feb 21Mar 21 – Apr 4Mar 21 – Mar 28
South JordanMar 21 – Mar 28Apr 25 – May 9Apr 25 – May 2
MillcreekMar 28 – Apr 4May 2 – May 16May 2 – May 9
TaylorsvilleMar 3 – Mar 10Apr 7 – Apr 21Apr 7 – Apr 14
LehiApr 2 – Apr 9May 7 – May 21May 7 – May 14
LoganApr 10 – Apr 17May 15 – May 29May 15 – May 22
MurrayMar 28 – Apr 4May 2 – May 16May 2 – May 9
DraperMar 21 – Mar 28Apr 25 – May 9Apr 25 – May 2
BountifulMar 28 – Apr 4May 2 – May 16May 2 – May 9
RivertonMar 21 – Mar 28Apr 25 – May 9Apr 25 – May 2
Pleasant GroveMar 20 – Mar 27Apr 24 – May 8Apr 24 – May 1
RoyMar 25 – Apr 1Apr 29 – May 13Apr 29 – May 6
Spanish ForkMar 28 – Apr 4May 2 – May 16May 2 – May 9
KearnsMar 11 – Mar 18Apr 15 – Apr 29Apr 15 – Apr 22
Cottonwood HeightsApr 1 – Apr 8May 6 – May 20May 6 – May 13
TooeleApr 4 – Apr 11May 9 – May 23May 9 – May 16
MidvaleApr 1 – Apr 8May 6 – May 20May 6 – May 13
SpringvilleMar 28 – Apr 4May 2 – May 16May 2 – May 9
HolladayApr 1 – Apr 8May 6 – May 20May 6 – May 13
HerrimanMar 21 – Mar 28Apr 25 – May 9Apr 25 – May 2
ClearfieldApr 1 – Apr 8May 6 – May 20May 6 – May 13
KaysvilleMar 22 – Mar 29Apr 26 – May 10Apr 26 – May 3

Showing the 30 most populous of 67 Utah cities. Dates are estimates from each city's NOAA frost normals and university extension timing guidelines. See all Utah cities.

Frequently Asked Questions

When should I plant cosmos in Utah?

In a typical Utah location, start seeds indoors Mar 27 – Apr 3, then sow outdoors May 1 – May 15, then transplant outdoors May 1 – May 8. Across the state, the outdoor planting window starts as early as Mar 21 in Saint George and as late as Jun 11 in Heber City.

When is the last frost in Utah?

The average last spring frost in Utah ranges from March 14 in Saint George to June 4 in Heber City, based on NOAA 1991–2020 climate normals.

How long do cosmos take to grow?

Cosmos typically take 60–90 days from planting to harvest. Easy from direct seed 1-3 weeks after last frost; can also start indoors 3-4 weeks early.

Other Crops in Utah

When to plant cosmos in other states

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