When to Plant Sunflower in Tooele County, UT
Sunflowers are tall, cheerful annuals grown for their edible seeds and as pollinator magnets. They come in sizes from 2-foot dwarfs to 12-foot giants.
Tooele County, Utah is in USDA Zone 6a. The average last spring frost is May 1 and the first fall frost is October 17, giving you a growing season of approximately 169 days.
At an elevation of 4,309 feet, Tooele County receives approximately 12.6 inches of rainfall annually with predominantly loam soil. Summer highs average 89°F, providing good warmth for Sunflower during the growing season. With low rainfall, drip irrigation is essential for growing Sunflower successfully. Mulch heavily to conserve soil moisture.
Tooele County Soil Profile
Soil Type
Loam
Soil pH
6.3-7.8
Drainage
Well Drained
Plant Planting Risk Windows
Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.
Plant Water Budget
Water stress score is 10/10 — consider drought-tolerant varieties and mulching
Sunflower Planting Timeline — Tooele County, UT
Sunflower Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 6 | Mar 6 – Mar 20 |
| Transplant Outdoors | May 15 | May 15 – May 29 |
| Direct Sow | May 8 | May 8 – May 29 |
| Harvest | July 24 | Jul 24 – Sep 11 |
Plant 1" deep · 18" apart · Rows 30" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
Sun
Full Sun (6-8+ hours)
Water
Low — drought tolerant
Days to Maturity
70–100 days
Soil pH
6 – 7.5
USDA Zone
Zone 6a
Growing Season
169 days
Growing Tips for Tooele County
Direct sow after last frost. Stake tall varieties in windy areas. Harvest seed heads when the back turns brown and seeds are plump. Dry heads upside down.
Companion Planting
Good Companions
Avoid Planting Near
Level Up Your Garden
Sunflower in Other Locations
Frequently Asked Questions
When should I plant Sunflower in Tooele County, UT?
Tooele County is in Zone 6a with an average last frost of May 1. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.
What planting zone is Tooele County, UT?
Tooele County, Utah is in USDA Hardiness Zone 6a. The average last spring frost is May 1 and first fall frost is October 17.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Tooele County gardeners in Zone 6a organize planting dates, track what's growing, and never miss a planting window.
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