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When to plant onion in Connecticut

Connecticut spans USDA zones 6a–7a, so the right time to plant onion shifts by weeks across the state. The window to transplant seedlings outdoors runs from about March 8 in Bridgeport to April 10 in Torrington — below are local dates for 35 cities, each computed from its own frost dates.

In Bridgeportthe onion transplant out window (March 8–March 22) has passed for this year.
CityZoneLast frostFirst frostTransplant out
Bridgeport7aApril 5November 6March 8 – March 22
Stamford7aApril 17October 23March 20 – April 3
New Haven7aApril 17October 27March 20 – April 3
Hartford6bApril 17October 26March 20 – April 3
Waterbury6bApril 26October 16March 29 – April 12
Norwalk7aApril 17October 23March 20 – April 3
Danbury6bMay 1October 14April 3 – April 17
New Britain6bApril 17October 26March 20 – April 3

Onion in Connecticut: FAQ

When can I plant onion in Connecticut?

Across Connecticut, the time to transplant onion spans roughly March 8 in Bridgeport to April 10 in Torrington, each following that city's local frost dates.

Does the onion planting date vary across Connecticut?

Yes. Connecticut publishes 35 cities with their own frost dates, so the right onion planting window shifts by weeks between the warmest and coldest parts of the state — use your city's page for the exact dates.

How long does onion take to grow in Connecticut?

Onion takes about 90–110 days to reach harvest once planted — check that this fits inside your city's frost-free season on its place page.

Planting reminders

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An email when it’s time to start seeds, transplant, and sow — timed to your frost dates. Double opt-in, one-click unsubscribe, no spam.

Onion planting guide →All Connecticut cities →Connecticut planting calendar →
When to Plant Onion in Connecticut — Frost-Based Dates by City — BlissGarden