FrostCal

When to Plant Cosmos in Kansas

In a typical Kansas location, start seeds indoors Mar 16 – Mar 23, then sow outdoors Apr 20 – May 4, then transplant outdoors Apr 20 – Apr 27. Across the state, the outdoor planting window starts as early as Apr 11 in Kansas City and as late as May 5 in Garden 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
WichitaMar 14 – Mar 21Apr 18 – May 2Apr 18 – Apr 25
Overland ParkMar 13 – Mar 20Apr 17 – May 1Apr 17 – Apr 24
Kansas CityMar 7 – Mar 14Apr 11 – Apr 25Apr 11 – Apr 18
OlatheMar 13 – Mar 20Apr 17 – May 1Apr 17 – Apr 24
TopekaMar 19 – Mar 26Apr 23 – May 7Apr 23 – Apr 30
LawrenceMar 15 – Mar 22Apr 19 – May 3Apr 19 – Apr 26
ShawneeMar 7 – Mar 14Apr 11 – Apr 25Apr 11 – Apr 18
ManhattanMar 19 – Mar 26Apr 23 – May 7Apr 23 – Apr 30
LenexaMar 13 – Mar 20Apr 17 – May 1Apr 17 – Apr 24
SalinaMar 21 – Mar 28Apr 25 – May 9Apr 25 – May 2
HutchinsonMar 21 – Mar 28Apr 25 – May 9Apr 25 – May 2
LeavenworthMar 15 – Mar 22Apr 19 – May 3Apr 19 – Apr 26
LeawoodMar 13 – Mar 20Apr 17 – May 1Apr 17 – Apr 24
Dodge CityMar 24 – Mar 31Apr 28 – May 12Apr 28 – May 5
Garden CityMar 31 – Apr 7May 5 – May 19May 5 – May 12
EmporiaMar 18 – Mar 25Apr 22 – May 6Apr 22 – Apr 29
Junction CityMar 15 – Mar 22Apr 19 – May 3Apr 19 – Apr 26
DerbyMar 17 – Mar 24Apr 21 – May 5Apr 21 – Apr 28
Prairie VillageMar 7 – Mar 14Apr 11 – Apr 25Apr 11 – Apr 18
HaysMar 22 – Mar 29Apr 26 – May 10Apr 26 – May 3
GardnerMar 16 – Mar 23Apr 20 – May 4Apr 20 – Apr 27
LiberalMar 23 – Mar 30Apr 27 – May 11Apr 27 – May 4
PittsburgMar 10 – Mar 17Apr 14 – Apr 28Apr 14 – Apr 21
NewtonMar 17 – Mar 24Apr 21 – May 5Apr 21 – Apr 28
Great BendMar 27 – Apr 3May 1 – May 15May 1 – May 8
McPhersonMar 21 – Mar 28Apr 25 – May 9Apr 25 – May 2
El DoradoMar 16 – Mar 23Apr 20 – May 4Apr 20 – Apr 27
AndoverMar 13 – Mar 20Apr 17 – May 1Apr 17 – Apr 24
OttawaMar 21 – Mar 28Apr 25 – May 9Apr 25 – May 2
WinfieldMar 19 – Mar 26Apr 23 – May 7Apr 23 – Apr 30

Showing the 30 most populous of 40 Kansas cities. Dates are estimates from each city's NOAA frost normals and university extension timing guidelines. See all Kansas cities.

Frequently Asked Questions

When should I plant cosmos in Kansas?

In a typical Kansas location, start seeds indoors Mar 16 – Mar 23, then sow outdoors Apr 20 – May 4, then transplant outdoors Apr 20 – Apr 27. Across the state, the outdoor planting window starts as early as Apr 11 in Kansas City and as late as May 5 in Garden City.

When is the last frost in Kansas?

The average last spring frost in Kansas ranges from April 4 in Kansas City to April 28 in Garden 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 Kansas

When to plant cosmos in other states

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