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When to Plant Watermelon in Apache County, AZ

Watermelon is a sprawling vine crop that produces sweet, juicy fruits in hot weather. Varieties range from personal-sized icebox types to 50-pound 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 Watermelon during the growing season. Sandy soil warms quickly in spring โ€” great for early planting โ€” but Watermelon will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Watermelon 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: Apr 4 Transplant: May 23 🍅 Harvest: Aug 1 – Sep 19
Recommended (50%) ✓ Fits season (10 days to spare)
Start indoors: Apr 15 Transplant: Jun 3 🍅 Harvest: Aug 12 – Sep 30
Safe Start (90%) ✓ Fits season (7 days to spare)
Start indoors: May 4 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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.3″/week
You supply
1.2″/week
Watering frequency 2-3 times/week
Season total 1,564 gal / 100 sq ft
Drought risk

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

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

Watermelon Planting Timeline โ€” Apache County, AZ

Watermelon Planting Calendar

Activity When Date Range
Start Indoors April 15 Apr 15 โ€“ Apr 29
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 30" apart ยท Rows 42" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
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

Moderate โ€” regular watering

Days to Maturity

70โ€“100 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 5b

Growing Season

143 days

Growing Tips for Apache County

Start seeds indoors 3-4 weeks early or direct sow after soil is warm. Plant on mounds with plenty of space. Check ripeness by looking for a yellow ground spot and dull thump when tapped.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Level Up Your Garden

Frequently Asked Questions

When should I plant Watermelon in Apache County, AZ?

Apache County is in Zone 5b with an average last frost of May 20. Plan your Watermelon 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.

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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: April 2026.