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When to Plant Sunflower in Apache 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.

Apache County, Arizona is in USDA Zone 5b. The average last spring frost is May 20 and the first fall frost is October 10, giving you a growing season of approximately 143 days.

At an elevation of 7,720 feet, Apache County receives approximately 9.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 92ยฐF, providing good warmth for Sunflower during the growing season. 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.

Apache County, AZ (Zone 5b) Short season
143 days
Last Spring Frost May 20
143 growing days
First Fall Frost October 10

Apache County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.2-8.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (14 days to spare)
Start indoors: Mar 14 Transplant: May 23 🍅 Harvest: Aug 1 – Sep 19
Recommended (50%) ✓ Fits season (10 days to spare)
Start indoors: Mar 25 Transplant: Jun 3 🍅 Harvest: Aug 12 – Sep 30
Safe Start (90%) ✓ Fits season (7 days to spare)
Start indoors: Apr 13 Transplant: Jun 22 🍅 Harvest: Aug 31 – Oct 19

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.

Soil Compatibility in Apache County

How your county's soil matches Sunflower's growing requirements.

Soil pH

Your soil pH (7.2โ€“8.7) is more alkaline than Sunflower prefers (6.0โ€“7.5). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Apache County warms quickly in spring but drains fast. Sunflower will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Sunflower.

Organic Matter

Organic matter is low (0.8%). Add 2-3 inches of compost before planting Sunflower.

How to Plant Sunflower

1"
Planting Depth
18"
Between Plants
30"
Between Rows

Succession Planting Sunflower

2
successive plantings in your 143-day season

Sow every 8 weeks. Last sowing by Jul 02 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.3″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 571 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Sunflower

Sunflower needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Sunflower Needs Rainfall You Supplement Action
Jan โ€” 0.7" 0" โ„๏ธ Dormant
Feb โ€” 0.5" 0" โ„๏ธ Dormant
Mar โ€” 0.6" 0" โ„๏ธ Dormant
Apr โ€” 0.3" 0" โ„๏ธ Dormant
May 2.2" 0.2" 2" ๐Ÿšฟ Regular watering
Jun 2.2" 0.3" 1.9" ๐Ÿšฟ Regular watering
Jul 2.2" 1.7" 0.5" ๐Ÿ’ง Light watering
Aug 2.2" 2" 0.2" ๐Ÿ’ง Light watering
Sep 2.2" 1.2" 1" ๐Ÿ’ง Light watering
Oct 2.2" 0.8" 1.4" ๐Ÿšฟ Regular watering
Nov โ€” 0.6" 0" โ„๏ธ Dormant
Dec โ€” 0.6" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Oct in Apache County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Sunflower Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" โ€” every day above 50ยฐF deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Sunflower needs ~1,615 GDD — county provides 2,717 GDD Excellent fit

Sunflower Planting Timeline โ€” Apache County, AZ

Sunflower Planting Calendar

Activity When Date Range
Start Indoors March 25 Mar 25 โ€“ Apr 8
Transplant Outdoors June 3 Jun 3 โ€“ Jun 17
Direct Sow May 27 May 27 โ€“ Jun 17
Harvest August 12 Aug 12 โ€“ Sep 30

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

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.5"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

70โ€“100 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 5b

๐Ÿ“† Growing Season

143 days in Apache County

Growing Tips for Sunflower in Apache County

Direct sow Sunflower outdoors after May 20 in Apache County when soil has warmed and frost danger has passed.

Sandy soil in Apache County dries quickly โ€” mulch Sunflower with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

Common pests for Sunflower in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

Apache County receives only 9" of rain annually. Sunflower needs consistent moisture โ€” install drip irrigation or water deeply 2-3 times per week.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sunflower in Apache County, AZ?

Apache County is in Zone 5b with an average last frost of May 20. Plan your Sunflower planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Apache County, AZ?

Apache County, Arizona is in USDA Hardiness Zone 5b. The average last spring frost is May 20 and first fall frost is October 10.

๐ŸŒฑ

Plan Your Garden with Confidence

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

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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