When to Plant Sunflowers in Connecticut
Few things bring more joy than a row of sunflowers turning their faces to the sun. Easy, dramatic, and pollinator-friendly.
The Short Answer
Connecticut Frost Dates
Your planting dates depend on which part of Connecticut you're in. Here are the frost date ranges by region:
| Region | Zones | Last Frost (Spring) | First Frost (Fall) |
|---|---|---|---|
| Northern Connecticut | 5b, 6a | May 1 - May 15 | Sep 25 - Oct 10 |
| Coastal Connecticut | 6b, 7a | Apr 15 - May 1 | Oct 10 - Oct 25 |
Sunflowers Planting Schedule for Connecticut
Northern Connecticut (Zones 5b, 6a)
Average last frost: May 1 - May 15 · Average first frost: Sep 25 - Oct 10
Coastal Connecticut (Zones 6b, 7a)
Average last frost: Apr 15 - May 1 · Average first frost: Oct 10 - Oct 25
Growing Sunflowers in Connecticut
Sunflowers in Connecticut's Climate
Sunflowers are nearly foolproof in moderate climates. Direct sow after frost and watch them grow a foot or more per week in the summer heat. Succession plant every 2 weeks through late June for blooms all summer. Your reliable warm season gives even the tallest mammoth varieties plenty of time to mature.
Soil Considerations for Connecticut
Rocky New England soil common. Acidic in many areas. Raised beds popular for dealing with rocky ground. Make sure soil has warmed to at least 55°F before planting sunflowers outside.
Connecticut Climate & Growing Season
Four distinct seasons. Maritime influence moderates coastal temperatures. Shorter growing season inland. Sunflowers cannot tolerate any frost, so wait until all frost danger has passed before transplanting outside. Watch local forecasts carefully in spring.
Growing season length varies across Connecticut: Northern Connecticut (5b, 6a) has a last frost around May 1 - May 15, while Coastal Connecticut (6b, 7a) sees frost end around Apr 15 - May 1. This difference matters for sunflowers — transplant timing shifts by several weeks across the state.
Growing Tips
Direct sow is preferred — sunflowers don't love transplanting. Succession plant every 2 weeks for blooms all summer.
Companion Planting
Plant sunflowers alongside these companions for better growth:
Keep sunflowers away from:
The Bottom Line
Last reviewed: March 29, 2026