When to Plant Sunflowers in Indiana
Few things bring more joy than a row of sunflowers turning their faces to the sun. Easy, dramatic, and pollinator-friendly.
The Short Answer
Indiana Frost Dates
Your planting dates depend on which part of Indiana you're in. Here are the frost date ranges by region:
| Region | Zones | Last Frost (Spring) | First Frost (Fall) |
|---|---|---|---|
| Northern Indiana | 5b, 6a | Apr 25 - May 10 | Oct 1 - Oct 15 |
| Central Indiana | 6a, 6b | Apr 15 - May 1 | Oct 10 - Oct 25 |
| Southern Indiana | 6b | Apr 10 - Apr 25 | Oct 15 - Nov 1 |
Sunflowers Planting Schedule for Indiana
Northern Indiana (Zones 5b, 6a)
Average last frost: Apr 25 - May 10 · Average first frost: Oct 1 - Oct 15
Central Indiana (Zones 6a, 6b)
Average last frost: Apr 15 - May 1 · Average first frost: Oct 10 - Oct 25
Southern Indiana (Zones 6b)
Average last frost: Apr 10 - Apr 25 · Average first frost: Oct 15 - Nov 1
Growing Sunflowers in Indiana
Sunflowers in Indiana'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 Indiana
Clay-heavy soils common statewide. Rich but can have drainage issues. Raised beds help with heavy clay. Make sure soil has warmed to at least 55°F before planting sunflowers outside.
Indiana Climate & Growing Season
Four seasons. Hot, humid summers. Adequate rainfall for most crops. Occasional late spring frosts catch gardeners off guard. 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 Indiana: Northern Indiana (5b, 6a) has a last frost around Apr 25 - May 10, while Southern Indiana (6b) sees frost end around Apr 10 - Apr 25. 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