FrostCal

When to Plant Onions in Connecticut

In a typical Connecticut location, start seeds indoors Feb 7 – Feb 21, then transplant outdoors Mar 21 – Apr 4. Across the state, the outdoor planting window starts as early as Mar 8 in Bridgeport and as late as Apr 10 in Torrington.

Method Start indoors, then transplant
Days to maturity 90–120 days

Start seeds indoors 8-10 weeks before last frost (or use sets/transplants); set out 2-4 weeks before last frost, very cold-tolerant as seedlings.

Onions Planting Dates by City

CityStart indoorsTransplant
BridgeportJan 25 – Feb 8Mar 8 – Mar 22
New HavenFeb 6 – Feb 20Mar 20 – Apr 3
StamfordFeb 6 – Feb 20Mar 20 – Apr 3
North StamfordFeb 6 – Feb 20Mar 20 – Apr 3
HartfordFeb 6 – Feb 20Mar 20 – Apr 3
WaterburyFeb 15 – Mar 1Mar 29 – Apr 12
NorwalkFeb 6 – Feb 20Mar 20 – Apr 3
DanburyFeb 9 – Feb 23Mar 23 – Apr 6
East NorwalkFeb 6 – Feb 20Mar 20 – Apr 3
New BritainFeb 6 – Feb 20Mar 20 – Apr 3
West HartfordFeb 6 – Feb 20Mar 20 – Apr 3
BristolFeb 14 – Feb 28Mar 28 – Apr 11
MeridenFeb 15 – Mar 1Mar 29 – Apr 12
HamdenFeb 7 – Feb 21Mar 21 – Apr 4
FairfieldJan 25 – Feb 8Mar 8 – Mar 22
West HavenFeb 6 – Feb 20Mar 20 – Apr 3
MilfordJan 25 – Feb 8Mar 8 – Mar 22
StratfordJan 25 – Feb 8Mar 8 – Mar 22
City of Milford (balance)Jan 25 – Feb 8Mar 8 – Mar 22
East HartfordFeb 6 – Feb 20Mar 20 – Apr 3
MiddletownFeb 15 – Mar 1Mar 29 – Apr 12
EnfieldFeb 10 – Feb 24Mar 24 – Apr 7
SouthingtonFeb 15 – Mar 1Mar 29 – Apr 12
SheltonFeb 14 – Feb 28Mar 28 – Apr 11
NorwichFeb 3 – Feb 17Mar 17 – Mar 31
TrumbullJan 25 – Feb 8Mar 8 – Mar 22
West TorringtonFeb 27 – Mar 13Apr 10 – Apr 24
TorringtonFeb 27 – Mar 13Apr 10 – Apr 24
GlastonburyFeb 6 – Feb 20Mar 20 – Apr 3
NaugatuckFeb 7 – Feb 21Mar 21 – Apr 4

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 onions in Connecticut?

In a typical Connecticut location, start seeds indoors Feb 7 – Feb 21, then transplant outdoors Mar 21 – Apr 4. Across the state, the outdoor planting window starts as early as Mar 8 in Bridgeport and as late as Apr 10 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 onions take to grow?

Onions typically take 90–120 days from planting to harvest. Start seeds indoors 8-10 weeks before last frost (or use sets/transplants); set out 2-4 weeks before last frost, very cold-tolerant as seedlings.

Other Crops in Connecticut

When to plant onions in other states

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