Connecticut planting calendar

When to plant broccoli in Connecticut — sow, transplant & harvest dates

Connecticut is mostly USDA zone 6b (range 5b-7b). Dates below are derived from broccoli's frost tolerance and Connecticut's frost window — not generic national averages.

Broccoli planting timetable for Connecticut

Stage	When in Connecticut	Anchor
Start seeds indoors	mid-March (March 14)	6 weeks before the last frost (late April)
Transplant outside	mid-April (April 11)	14 days before the last frost (late April)
First harvest (estimate)	late June (June 30)	~80 days from transplant

Dates are state-wide averages for the dominant zone. Local microclimates — elevation, urban heat, coastal moderation — can shift the window by 1-2 weeks. Use the frost-date calculator for a date tuned to your town.

Why Connecticut's climate shifts the broccoli dates

Connecticut's last spring frost averages late April and first fall frost mid-October, which sets the whole planting clock. Connecticut has a classic four-season New England climate with a coastal strip a full zone milder than the inland hills. Sow early — broccoli bolt once daytime temperatures hold above 24 °C, so the earlier they go in, the longer the harvest.

Start seeds indoors 6–8 weeks before last frost; transplant outdoors 2–4 weeks before last spring frost when soil reaches at least 7 °C (45 °F). Mature plants withstand temperatures as low as −6 °C (21 °F). Heads button (form premature small curds) when exposed to temperatures below 10 °C (50 °F) for extended periods as young seedlings, so harden off carefully. In zones 8–10, a second crop is practical as a fall planting, set out in late summer for harvest before hard freezes.

Frost-risk note

Don't plant before late April — a hard freeze can still set young plants back. In the northwest hills near Litchfield (zone 5b) the safe date runs a week or two later.

Regional variation within Connecticut

the northwest hills near Litchfield (zone 5b) runs roughly 1-2 weeks behind the state average; the Long Island Sound shoreline (zone 7b) can plant 1-2 weeks earlier.

Hartford — USDA zone 6b
New Haven — USDA zone 7a
Bridgeport — USDA zone 7a
Stamford — USDA zone 7a

What else to plant in Connecticut around then

The same early window suits peas, lettuce, spinach, and onion sets.

Quick-grow guide

Sun: Full sun — 6+ hours direct.
Soil temperature for germination: 7–29 °C (45–85 °F).
Spacing: 18–24 inches (45–60 cm) between plants.
Days to harvest: ~80 days from planting out.

Frequently asked questions

When is the best time to plant broccoli in Connecticut?

In Connecticut (mostly USDA zone 6b), sow broccoli indoors around mid-March, transplant outdoors mid-April (before the last frost, late April), and harvest from late June. Broccoli are cold-hardy — they tolerate frost and actively prefer cool weather, so they go in well before the last spring frost and bolt in summer heat.

What USDA zone is Connecticut?

Most of Connecticut sits in USDA hardiness zone 6b, with the state spanning roughly 5b-7b from the northwest hills near Litchfield (zone 5b) to the Long Island Sound shoreline (zone 7b). The last spring frost averages late April and the first fall frost mid-October.

Can you grow broccoli in Connecticut?

Yes. Connecticut's dominant zone 6b supports broccoli — the key is timing. Broccoli are cold-hardy — they tolerate frost and actively prefer cool weather, so they go in well before the last spring frost and bolt in summer heat.

Does the planting date change across Connecticut?

the northwest hills near Litchfield (zone 5b) runs roughly 1-2 weeks behind the state average; the Long Island Sound shoreline (zone 7b) can plant 1-2 weeks earlier.

What else can I plant in Connecticut around the same time?

The same early window suits peas, lettuce, spinach, and onion sets.

Source and methodology

State zone spans from the USDA Plant Hardiness Zone Map (2023); frost-date averages from NOAA Climate Data Online. Hot-state two-season timing cross-checked against the UF/IFAS Florida Gardening Calendar and the University of Arizona Cooperative Extension planting calendar. Curated by the Growli editorial team.