When to plant Onion sets in Connecticut

In spring, from Mar 1 – Apr 1 in Bridgeport to Apr 10 – May 1 in Torrington.

In fall, Oct 1 – Dec 1.

USDA's earliest safe spring and latest safe fall planting dates, matched to each place's average frost dates.

Onion sets planting dates by place in Connecticut
PlaceSpringFall
AnsoniaMar 10 – Apr 1Spring-planted
BridgeportMar 1 – Apr 1Oct 1 – Dec 1Now
BristolMar 10 – Apr 1Spring-planted
DanburyMar 10 – Apr 10Spring-planted
DerbyMar 10 – Apr 1Spring-planted
GrotonMar 10 – Apr 1Not listed
HartfordMar 10 – Apr 1Not listed
MeridenMar 10 – Apr 10Spring-planted
MiddletownMar 10 – Apr 10Spring-planted
MilfordMar 1 – Apr 1Oct 1 – Dec 1Now
NaugatuckMar 10 – Apr 1Not listed
New BritainMar 10 – Apr 1Not listed
New HavenMar 10 – Apr 1Not listed
New LondonMar 10 – Apr 1Not listed
NorwalkMar 10 – Apr 1Spring-planted
NorwichMar 1 – Apr 1Spring-planted
SheltonMar 10 – Apr 1Spring-planted
StamfordMar 10 – Apr 1Spring-planted
TorringtonApr 10 – May 1Spring-planted
WaterburyMar 10 – Apr 10Spring-planted
West HavenMar 10 – Apr 1Not listed

Planting dates: USDA Home and Garden Bulletin No. 9 (1967), tables 4 and 5. Frost dates: NOAA U.S. Climate Normals 1991–2020. The full USDA table for onion sets.