When to Plant Sunflowers in Maine
Few things bring more joy than a row of sunflowers turning their faces to the sun. Easy, dramatic, and pollinator-friendly.
The Short Answer
Maine Frost Dates
Your planting dates depend on which part of Maine you're in. Here are the frost date ranges by region:
| Region | Zones | Last Frost (Spring) | First Frost (Fall) |
|---|---|---|---|
| Northern Maine | 3b, 4a, 4b | May 20 - Jun 5 | Sep 10 - Sep 25 |
| Central Maine | 4b, 5a | May 10 - May 25 | Sep 20 - Oct 5 |
| Southern/Coastal Maine | 5a, 5b, 6a | May 1 - May 15 | Sep 25 - Oct 15 |
Sunflowers Planting Schedule for Maine
Northern Maine (Zones 3b, 4a, 4b)
Average last frost: May 20 - Jun 5 · Average first frost: Sep 10 - Sep 25
Central Maine (Zones 4b, 5a)
Average last frost: May 10 - May 25 · Average first frost: Sep 20 - Oct 5
Southern/Coastal Maine (Zones 5a, 5b, 6a)
Average last frost: May 1 - May 15 · Average first frost: Sep 25 - Oct 15
Growing Sunflowers in Maine
Sunflowers in Maine's Climate
Sunflowers are surprisingly well-suited to cold climates — they grow fast enough to bloom before frost even in zones with 100-day seasons. Direct sow 1-2 weeks after your last frost. The intense summer daylight in northern latitudes actually produces taller stalks and larger heads. Choose varieties under 90 days to maturity for the shortest-season areas.
Soil Considerations for Maine
Acidic, rocky soils. Blueberries thrive naturally. Raised beds common to deal with rocks. Amendment with lime needed for many vegetables. Make sure soil has warmed to at least 55°F before planting sunflowers outside.
Maine Climate & Growing Season
Short growing season but long summer days help. Maritime influence on coast. Season extension techniques very valuable. 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 Maine: Northern Maine (3b, 4a, 4b) has a last frost around May 20 - Jun 5, while Southern/Coastal Maine (5a, 5b, 6a) sees frost end around May 1 - May 15. 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