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When to plant Sunflower in Apache County, AZ

In Apache County, Sunflower is a spring-only crop. Plant May 20–June 10 once soil hits 50°F.

When to Plant Sunflower in Apache County, AZ

Apache County, Arizona Zone 6b August

What to do in August

Each item below is timed to Apache County, Arizona's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost May 20
Avg. first frost October 10
Soil temp (4") 56°F
Watering High
Pest pressure High
Daylight 13.3 hrs
  1. Harvest sunflower as they ripen

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

September will be here before you know it — start on
  • First harvests: sunflower

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Sunflower (Helianthus annuus) is a fast-growing North American native annual famous for its towering stems and brilliant yellow heads. It thrives in full sun and heat, producing large, pollen-rich blooms that attract bees, butterflies, and seed-eating birds. Varieties range from 18-inch dwarfs to 12-foot giants and nearly every color except blue.

Apache County, Arizona is in USDA Zone 6b. 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 92°F, providing good warmth for Sunflower during the growing season. Sandy soil warms quickly in spring — great for early planting — 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.

Annual Blooms in Summer Pollinator-friendly Good for cutting
Apache County, AZ (Zone 6b) 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

Sunflower Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 18 Transplant: May 9 🌸 Bloom: Aug 1 – Oct 31
Recommended (50%) ✗ May not fit
Start indoors: Apr 29 Transplant: May 20 🌸 Bloom: Aug 12 – Nov 11
Safe Start (90%) ✗ May not fit
Start indoors: May 18 Transplant: Jun 8 🌸 Bloom: Aug 31 – Nov 30

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 (7.2–8.7) is more alkaline than Sunflower prefers (6.0–7.5). 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
24"
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.

Sunflower 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 — 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 0.7" 0" ❄️ Dormant
Feb 0.5" 0" ❄️ Dormant
Mar 0.6" 0" ❄️ Dormant
Apr 0.3" 0" ❄️ Dormant
May 2.2" 0.2" 2" 🚿 Regular watering
Jun 2.2" 0.3" 1.9" 🚿 Regular watering
Jul 2.2" 1.7" 0.5" 💧 Light watering
Aug 2.2" 2" 0.2" 💧 Light watering
Sep 2.2" 1.2" 1" 💧 Light watering
Oct 2.2" 0.8" 1.4" 🚿 Regular watering
Nov 0.6" 0" ❄️ Dormant
Dec 0.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Apache County). Supplement amounts are based on average rainfall — 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" — every day above 50°F 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 — Apache County, AZ

Sunflower Planting Calendar

Activity When Date Range
Start Indoors April 29 Apr 29 – May 13
Transplant Outdoors May 20 May 20 – Jun 3
Direct Sow May 20 May 20 – Jun 10
Bloom August 12 Aug 12 – Nov 11

Plant 1" deep · 18" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Start Indoors Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July
August Bloom
September Bloom
October Bloom
November Bloom
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · 1-2 times/week

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6b

📆 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 — 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 — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct-sow 1 inch deep after last frost; germination takes 7-14 days at 65-75°F soil. Sunflowers dislike root disturbance so direct sowing is strongly preferred over transplanting. Plant in succession every 2 weeks for extended bloom. Stake tall varieties. Avoid overwatering — they tolerate drought once established. Birds will self-deadhead seed heads; leave them up through fall for wildlife.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes
  • Pole_beans

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 6b with an average last frost of May 20. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Apache County, AZ?

Apache County, Arizona is in USDA Hardiness Zone 6b. The average last spring frost is May 20 and first fall frost is October 10.

When should I plant Sunflower in Apache County, AZ?

In Apache County, AZ, plant Sunflower after the last frost (around May 20) and before the first frost (around October 10). Best results when soil holds above 50°F.

What growing zone is Apache County, AZ for Sunflower?

Apache County sits in USDA Zone 6b. Sunflower grows reliably in zones 2a through 11b, so it's a good fit here.

Can Sunflower grow in Apache County's climate?

Yes — Sunflower grows well in Apache County's temperate climate. Apache County averages a 143-day frost-free season, with last frost around May 20 and first frost around October 10.

🌱

Your Apache County Garden Planner — Free

A 22-page printable planner built for Apache County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Apache County, AZ. Local conditions may vary. Last updated: August 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.