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When to Plant Acorn Squash in Pierce County, WA

Acorn squash is a small winter squash with dark green, ribbed skin and mildly sweet orange flesh. It is perfect for stuffing and roasting as individual servings.

Pierce County, Washington is in USDA Zone 8a. The average last spring frost is April 13 and the first fall frost is October 30, giving you a growing season of approximately 200 days.

At an elevation of 168 feet, Pierce County receives approximately 48.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Acorn Squash to ensure they mature before fall.

Pierce County, WA (Zone 8a) Long season
200 days
Last Spring Frost April 13
200 growing days
First Fall Frost October 30

Pierce County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (59 days to spare)
Start indoors: Mar 7 Transplant: Apr 18 🍅 Harvest: Jul 11 – Aug 15
Recommended (50%) ✓ Fits season (67 days to spare)
Start indoors: Mar 16 Transplant: Apr 27 🍅 Harvest: Jul 20 – Aug 24
Safe Start (90%) ✓ Fits season (59 days to spare)
Start indoors: Apr 18 Transplant: May 30 🍅 Harvest: Aug 22 – Sep 26

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
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Acorn Squash needs ~1,102 GDD — county provides 2,450 GDD Excellent fit

Acorn Squash Planting Timeline โ€” Pierce County, WA

Acorn Squash Planting Calendar

Activity When Date Range
Start Indoors March 16 Mar 16 โ€“ Mar 30
Transplant Outdoors April 27 Apr 27 โ€“ May 11
Direct Sow April 20 Apr 20 โ€“ May 11
Harvest July 20 Jul 20 โ€“ Aug 24

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

80โ€“100 days

Soil pH

5.5 โ€“ 7

USDA Zone

Zone 8a

Growing Season

200 days

Growing Tips for Pierce County

Direct sow after last frost. Harvest when the ground spot turns orange and the skin is hard. Acorn squash has a shorter storage life than butternut, lasting about 2 months.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Level Up Your Garden

Frequently Asked Questions

When should I plant Acorn Squash in Pierce County, WA?

Pierce County is in Zone 8a with an average last frost of April 13. Plan your Acorn Squash planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Pierce County, WA?

Pierce County, Washington is in USDA Hardiness Zone 8a. The average last spring frost is April 13 and first fall frost is October 30.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Pierce County gardeners in Zone 8a 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 Pierce County, WA. Local conditions may vary. Last updated: April 2026.