FrostCal

When to Plant Cosmos in Connecticut

In a typical Connecticut location, start seeds indoors Mar 21 – Mar 28, then sow outdoors Apr 25 – May 9, then transplant outdoors Apr 25 – May 2. Across the state, the outdoor planting window starts as early as Apr 12 in Bridgeport and as late as May 15 in Torrington.

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
BridgeportMar 8 – Mar 15Apr 12 – Apr 26Apr 12 – Apr 19
New HavenMar 20 – Mar 27Apr 24 – May 8Apr 24 – May 1
StamfordMar 20 – Mar 27Apr 24 – May 8Apr 24 – May 1
North StamfordMar 20 – Mar 27Apr 24 – May 8Apr 24 – May 1
HartfordMar 20 – Mar 27Apr 24 – May 8Apr 24 – May 1
WaterburyMar 29 – Apr 5May 3 – May 17May 3 – May 10
NorwalkMar 20 – Mar 27Apr 24 – May 8Apr 24 – May 1
DanburyMar 23 – Mar 30Apr 27 – May 11Apr 27 – May 4
East NorwalkMar 20 – Mar 27Apr 24 – May 8Apr 24 – May 1
New BritainMar 20 – Mar 27Apr 24 – May 8Apr 24 – May 1
West HartfordMar 20 – Mar 27Apr 24 – May 8Apr 24 – May 1
BristolMar 28 – Apr 4May 2 – May 16May 2 – May 9
MeridenMar 29 – Apr 5May 3 – May 17May 3 – May 10
HamdenMar 21 – Mar 28Apr 25 – May 9Apr 25 – May 2
FairfieldMar 8 – Mar 15Apr 12 – Apr 26Apr 12 – Apr 19
West HavenMar 20 – Mar 27Apr 24 – May 8Apr 24 – May 1
MilfordMar 8 – Mar 15Apr 12 – Apr 26Apr 12 – Apr 19
StratfordMar 8 – Mar 15Apr 12 – Apr 26Apr 12 – Apr 19
City of Milford (balance)Mar 8 – Mar 15Apr 12 – Apr 26Apr 12 – Apr 19
East HartfordMar 20 – Mar 27Apr 24 – May 8Apr 24 – May 1
MiddletownMar 29 – Apr 5May 3 – May 17May 3 – May 10
EnfieldMar 24 – Mar 31Apr 28 – May 12Apr 28 – May 5
SouthingtonMar 29 – Apr 5May 3 – May 17May 3 – May 10
SheltonMar 28 – Apr 4May 2 – May 16May 2 – May 9
NorwichMar 17 – Mar 24Apr 21 – May 5Apr 21 – Apr 28
TrumbullMar 8 – Mar 15Apr 12 – Apr 26Apr 12 – Apr 19
West TorringtonApr 10 – Apr 17May 15 – May 29May 15 – May 22
TorringtonApr 10 – Apr 17May 15 – May 29May 15 – May 22
GlastonburyMar 20 – Mar 27Apr 24 – May 8Apr 24 – May 1
NaugatuckMar 21 – Mar 28Apr 25 – May 9Apr 25 – May 2

Showing the 30 most populous of 86 Connecticut cities. Dates are estimates from each city's NOAA frost normals and university extension timing guidelines. See all Connecticut cities.

Frequently Asked Questions

When should I plant cosmos in Connecticut?

In a typical Connecticut location, start seeds indoors Mar 21 – Mar 28, then sow outdoors Apr 25 – May 9, then transplant outdoors Apr 25 – May 2. Across the state, the outdoor planting window starts as early as Apr 12 in Bridgeport and as late as May 15 in Torrington.

When is the last frost in Connecticut?

The average last spring frost in Connecticut ranges from April 5 in Bridgeport to May 8 in Torrington, 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 Connecticut

When to plant cosmos in other states

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