When to Plant Sunflowers in Utah
Few things bring more joy than a row of sunflowers turning their faces to the sun. Easy, dramatic, and pollinator-friendly.
The Short Answer
Utah Frost Dates
Your planting dates depend on which part of Utah you're in. Here are the frost date ranges by region:
| Region | Zones | Last Frost (Spring) | First Frost (Fall) |
|---|---|---|---|
| Wasatch Front (SLC) | 6a, 6b, 7a | Apr 20 - May 10 | Oct 1 - Oct 20 |
| Mountain Regions | 4a, 4b, 5a | May 25 - Jun 15 | Aug 25 - Sep 15 |
| Southern Utah | 6b, 7a, 7b | Apr 10 - May 1 | Oct 10 - Nov 1 |
Sunflowers Planting Schedule for Utah
Wasatch Front (SLC) (Zones 6a, 6b, 7a)
Average last frost: Apr 20 - May 10 · Average first frost: Oct 1 - Oct 20
Mountain Regions (Zones 4a, 4b, 5a)
Average last frost: May 25 - Jun 15 · Average first frost: Aug 25 - Sep 15
Southern Utah (Zones 6b, 7a, 7b)
Average last frost: Apr 10 - May 1 · Average first frost: Oct 10 - Nov 1
Growing Sunflowers in Utah
Sunflowers in Utah's Climate
Sunflowers love your heat and long days. Plant earlier than northern growers — from mid-March in many warm-zone areas. The intense sun produces vibrant colors and sturdy stalks. Multiple succession plantings can provide sunflower blooms from May through November.
Soil Considerations for Utah
Alkaline desert soils. Low organic matter. Saline soils in some areas. Heavy amendment with compost and sulfur needed. Make sure soil has warmed to at least 55°F before planting sunflowers outside.
Utah Climate & Growing Season
Arid climate. Intense sun. Low humidity. Wide temperature swings. Irrigation essential everywhere. 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 Utah: Wasatch Front (SLC) (6a, 6b, 7a) has a last frost around Apr 20 - May 10, while Southern Utah (6b, 7a, 7b) sees frost end around Apr 10 - 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