FrostCal

When to Plant Cosmos in Missouri

In a typical Missouri location, start seeds indoors Mar 11 – Mar 18, then sow outdoors Apr 15 – Apr 29, then transplant outdoors Apr 15 – Apr 22. Across the state, the outdoor planting window starts as early as Apr 2 in Sikeston and as late as Apr 28 in Kirksville.

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
Kansas CityMar 7 – Mar 14Apr 11 – Apr 25Apr 11 – Apr 18
St. LouisMar 4 – Mar 11Apr 8 – Apr 22Apr 8 – Apr 15
SpringfieldMar 7 – Mar 14Apr 11 – Apr 25Apr 11 – Apr 18
ColumbiaMar 8 – Mar 15Apr 12 – Apr 26Apr 12 – Apr 19
IndependenceMar 13 – Mar 20Apr 17 – May 1Apr 17 – Apr 24
Lee's SummitMar 16 – Mar 23Apr 20 – May 4Apr 20 – Apr 27
O'FallonMar 12 – Mar 19Apr 16 – Apr 30Apr 16 – Apr 23
Saint JosephMar 22 – Mar 29Apr 26 – May 10Apr 26 – May 3
Saint CharlesMar 11 – Mar 18Apr 15 – Apr 29Apr 15 – Apr 22
Blue SpringsMar 10 – Mar 17Apr 14 – Apr 28Apr 14 – Apr 21
Saint PetersMar 12 – Mar 19Apr 16 – Apr 30Apr 16 – Apr 23
FlorissantMar 5 – Mar 12Apr 9 – Apr 23Apr 9 – Apr 16
JoplinMar 12 – Mar 19Apr 16 – Apr 30Apr 16 – Apr 23
ChesterfieldMar 7 – Mar 14Apr 11 – Apr 25Apr 11 – Apr 18
Jefferson CityMar 11 – Mar 18Apr 15 – Apr 29Apr 15 – Apr 22
Cape GirardeauMar 8 – Mar 15Apr 12 – Apr 26Apr 12 – Apr 19
OakvilleMar 9 – Mar 16Apr 13 – Apr 27Apr 13 – Apr 20
WildwoodMar 15 – Mar 22Apr 19 – May 3Apr 19 – Apr 26
WentzvilleMar 13 – Mar 20Apr 17 – May 1Apr 17 – Apr 24
University CityMar 4 – Mar 11Apr 8 – Apr 22Apr 8 – Apr 15
BallwinMar 7 – Mar 14Apr 11 – Apr 25Apr 11 – Apr 18
LibertyMar 22 – Mar 29Apr 26 – May 10Apr 26 – May 3
RaytownMar 13 – Mar 20Apr 17 – May 1Apr 17 – Apr 24
MehlvilleMar 9 – Mar 16Apr 13 – Apr 27Apr 13 – Apr 20
KirkwoodMar 4 – Mar 11Apr 8 – Apr 22Apr 8 – Apr 15
Maryland HeightsMar 5 – Mar 12Apr 9 – Apr 23Apr 9 – Apr 16
GladstoneMar 7 – Mar 14Apr 11 – Apr 25Apr 11 – Apr 18
HazelwoodMar 5 – Mar 12Apr 9 – Apr 23Apr 9 – Apr 16
GrandviewMar 10 – Mar 17Apr 14 – Apr 28Apr 14 – Apr 21
Webster GrovesMar 4 – Mar 11Apr 8 – Apr 22Apr 8 – Apr 15

Showing the 30 most populous of 90 Missouri cities. Dates are estimates from each city's NOAA frost normals and university extension timing guidelines. See all Missouri cities.

Frequently Asked Questions

When should I plant cosmos in Missouri?

In a typical Missouri location, start seeds indoors Mar 11 – Mar 18, then sow outdoors Apr 15 – Apr 29, then transplant outdoors Apr 15 – Apr 22. Across the state, the outdoor planting window starts as early as Apr 2 in Sikeston and as late as Apr 28 in Kirksville.

When is the last frost in Missouri?

The average last spring frost in Missouri ranges from March 26 in Sikeston to April 21 in Kirksville, 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 Missouri

When to plant cosmos in other states

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