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When to Plant Butternut Squash in Mariposa County, CA

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.

Mariposa County, California is in USDA Zone 7b. The average last spring frost is April 18 and the first fall frost is November 9, giving you a growing season of approximately 205 days.

At an elevation of 192 feet, Mariposa County receives approximately 19.2 inches of rainfall annually with predominantly loam soil. Summer highs average 91ยฐF, providing good warmth for Butternut Squash during the growing season. With low rainfall, drip irrigation is essential for growing Butternut Squash successfully. Mulch heavily to conserve soil moisture.

Mariposa County, CA (Zone 7b) Long season
205 days
Last Spring Frost April 18
205 growing days
First Fall Frost November 9

Mariposa County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (80 days to spare)
Start indoors: Feb 24 Transplant: Apr 7 🍅 Harvest: Jul 7 – Aug 11
Recommended (50%) ✓ Fits season (65 days to spare)
Start indoors: Mar 21 Transplant: May 2 🍅 Harvest: Aug 1 – Sep 5
Safe Start (90%) ✓ Fits season (59 days to spare)
Start indoors: Apr 20 Transplant: Jun 1 🍅 Harvest: Aug 31 – Oct 5

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
0.4″/week
You supply
0.7″/week
Watering frequency 2-3 times/week
Season total 1,328 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” consider drought-tolerant varieties and mulching

Butternut Squash needs ~1,779 GDD — county provides 3,741 GDD Excellent fit

Butternut Squash Planting Timeline โ€” Mariposa County, CA

Butternut Squash Planting Calendar

Activity When Date Range
Start Indoors March 21 Mar 21 โ€“ Apr 4
Transplant Outdoors May 2 May 2 โ€“ May 16
Direct Sow April 25 Apr 25 โ€“ May 16
Harvest August 1 Aug 1 โ€“ Sep 5

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April Start Indoors Direct Sow
May Transplant Outdoors Direct Sow
June โ€”
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

85โ€“110 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 7b

Growing Season

205 days

Growing Tips for Mariposa 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 Mariposa County, CA?

Mariposa County is in Zone 7b with an average last frost of April 18. Plan your Butternut Squash planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Mariposa County, CA?

Mariposa County, California is in USDA Hardiness Zone 7b. The average last spring frost is April 18 and first fall frost is November 9.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Mariposa 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 Mariposa County, CA. Local conditions may vary. Last updated: April 2026.