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When to Plant Sunflower in Juab 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.

Juab County, Utah is in USDA Zone 5b. The average last spring frost is May 19 and the first fall frost is October 2, giving you a growing season of approximately 136 days.

At an elevation of 8,143 feet, Juab County receives approximately 23.3 inches of rainfall annually with predominantly loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Sunflower to ensure they mature before fall.

Juab County, UT (Zone 5b) Short season
136 days
Last Spring Frost May 19
136 growing days
First Fall Frost October 2

Juab County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (2 days to spare)
Start indoors: Mar 17 Transplant: May 26 🍅 Harvest: Aug 4 – Sep 22
Recommended (50%) ✓ Fits season (3 days to spare)
Start indoors: Mar 24 Transplant: Jun 2 🍅 Harvest: Aug 11 – Sep 29
Safe Start (90%) ✗ May not fit
Start indoors: Apr 14 Transplant: Jun 23 🍅 Harvest: Sep 1 – Oct 20

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

Plant needs
0.5″/week
Rainfall provides
0.7″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” consider drought-tolerant varieties and mulching

Sunflower needs ~1,105 GDD — county provides 1,768 GDD Excellent fit

Sunflower Planting Timeline โ€” Juab County, UT

Sunflower Planting Calendar

Activity When Date Range
Start Indoors March 24 Mar 24 โ€“ Apr 7
Transplant Outdoors June 2 Jun 2 โ€“ Jun 16
Direct Sow May 26 May 26 โ€“ Jun 16
Harvest August 11 Aug 11 โ€“ Sep 29

Plant 1" deep ยท 18" apart ยท Rows 30" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April Start Indoors
May Direct Sow
June Transplant Outdoors Direct Sow
July โ€”
August Harvest
September Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Low โ€” drought tolerant

Days to Maturity

70โ€“100 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 5b

Growing Season

136 days

Growing Tips for Juab 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

  • Potatoes

Level Up Your Garden

Frequently Asked Questions

When should I plant Sunflower in Juab County, UT?

Juab County is in Zone 5b with an average last frost of May 19. Plan your Sunflower planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Juab County, UT?

Juab County, Utah is in USDA Hardiness Zone 5b. The average last spring frost is May 19 and first fall frost is October 2.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Juab County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Juab County, UT. Local conditions may vary. Last updated: April 2026.