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When to Plant Sunflower in Graham County, AZ

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.

Graham County, Arizona is in USDA Zone 7b. The average last spring frost is April 6 and the first fall frost is November 5, giving you a growing season of approximately 213 days.

At an elevation of 2,604 feet, Graham County receives approximately 8 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 98ยฐF, so Sunflower may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring โ€” great for early planting โ€” but Sunflower will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Sunflower successfully. Mulch heavily to conserve soil moisture.

Graham County, AZ (Zone 7b) Long season
213 days
Last Spring Frost April 6
213 growing days
First Fall Frost November 5

Graham County Soil Profile

Soil Type

Sandy Loam

Soil pH

7-8.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (95 days to spare)
Start indoors: Jan 24 Transplant: Mar 28 🍅 Harvest: Jun 6 – Jul 25
Recommended (50%) ✓ Fits season (80 days to spare)
Start indoors: Feb 16 Transplant: Apr 20 🍅 Harvest: Jun 29 – Aug 17
Safe Start (90%) ✓ Fits season (84 days to spare)
Start indoors: Mar 12 Transplant: May 14 🍅 Harvest: Jul 23 – Sep 10

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
0.2″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 1,120 gal / 100 sq ft
Drought risk

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

Sunflower needs ~1,998 GDD — county provides 5,005 GDD Excellent fit

Sunflower Planting Timeline โ€” Graham County, AZ

Sunflower Planting Calendar

Activity When Date Range
Start Indoors February 16 Feb 16 โ€“ Mar 2
Transplant Outdoors April 20 Apr 20 โ€“ May 4
Direct Sow April 13 Apr 13 โ€“ May 4
Harvest June 29 Jun 29 โ€“ Aug 17

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

Month-by-Month Timeline

MonthActivities
January โ€”
February Start Indoors
March Start Indoors
April Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June Harvest
July Harvest
August Harvest
September โ€”
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 7b

Growing Season

213 days

Growing Tips for Graham 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 Graham County, AZ?

Graham County is in Zone 7b with an average last frost of April 6. Plan your Sunflower planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Graham County, AZ?

Graham County, Arizona is in USDA Hardiness Zone 7b. The average last spring frost is April 6 and first fall frost is November 5.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Graham County gardeners in Zone 7b 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 Graham County, AZ. Local conditions may vary. Last updated: April 2026.