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When to Plant Butternut Squash in La Paz County, AZ

Butternut squash is a popular winter squash with a long neck, small seed cavity, and sweet, nutty orange flesh. It stores exceptionally well for months.

La Paz County, Arizona is in USDA Zone 9b. The average last spring frost is February 2 and the first fall frost is December 6, giving you a growing season of approximately 307 days.

At an elevation of 4,875 feet, La Paz County receives approximately 17.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 105ยฐF, so Butternut Squash may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring โ€” great for early planting โ€” but Butternut Squash will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Butternut Squash successfully. Mulch heavily to conserve soil moisture.

La Paz County, AZ (Zone 9b) Year-round
307 days
Last Spring Frost February 2
307 growing days
First Fall Frost December 6

La Paz County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.2-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (186 days to spare)
Start indoors: Dec 21 Transplant: Jan 25 🍅 Harvest: Apr 26 – May 31
Recommended (50%) ✓ Fits season (174 days to spare)
Start indoors: Jan 5 Transplant: Feb 9 🍅 Harvest: May 11 – Jun 15
Safe Start (90%) ✓ Fits season (170 days to spare)
Start indoors: Jan 30 Transplant: Mar 6 🍅 Harvest: Jun 5 – Jul 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
1.0″/week
Rainfall provides
0.2″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 2,509 gal / 100 sq ft
Drought risk

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

Butternut Squash needs ~2,803 GDD — county provides 8,855 GDD Excellent fit

Butternut Squash Planting Timeline โ€” La Paz County, AZ

Butternut Squash Planting Calendar

Activity When Date Range
Start Indoors January 5 Jan 5 โ€“ Jan 19
Transplant Outdoors February 9 Feb 9 โ€“ Feb 23
Direct Sow February 2 Feb 2 โ€“ Feb 23
Harvest May 11 May 11 โ€“ Jun 15

Plant 1" deep ยท 30" apart ยท Rows 42" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

85โ€“110 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 9b

Growing Season

307 days

Growing Tips for La Paz County

Start seeds indoors 3 weeks early or direct sow after frost. Allow 6-8 feet for sprawling vines. Harvest when the skin is hard and uniformly tan. Cure in the sun for 10 days.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Level Up Your Garden

Frequently Asked Questions

When should I plant Butternut Squash in La Paz County, AZ?

La Paz County is in Zone 9b with an average last frost of February 2. Plan your Butternut Squash planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is La Paz County, AZ?

La Paz County, Arizona is in USDA Hardiness Zone 9b. The average last spring frost is February 2 and first fall frost is December 6.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help La Paz County gardeners in Zone 9b 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 La Paz County, AZ. Local conditions may vary. Last updated: April 2026.