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When to Plant Acorn Squash in Stanislaus County, CA

Stanislaus County, California Zone 9b May

May in Stanislaus County, California — your action list

Here's what deserves your attention in Stanislaus County, California this month. Everything below is tailored to Zone 9b and timed around your local frost dates.

Avg. last frost February 24
Avg. first frost November 28
Soil temp (4") 71°F
Watering Critical
Pest pressure High
Daylight 14 hrs
  1. Bring in the acorn squash

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

Looking ahead to June
  • First harvests: acorn squash

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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.

Stanislaus County, California is in USDA Zone 9b. The average last spring frost is February 24 and the first fall frost is November 28, giving you a growing season of approximately 277 days.

At an elevation of 2,887 feet, Stanislaus County receives approximately 15.2 inches of rainfall annually with predominantly loam soil. Summer highs average 94°F, providing good warmth for Acorn Squash during the growing season. With low rainfall, drip irrigation is essential for growing Acorn Squash successfully. Mulch heavily to conserve soil moisture.

Stanislaus County, CA (Zone 9b) Year-round
277 days
Last Spring Frost February 24
277 growing days
First Fall Frost November 28
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Stanislaus County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (163 days to spare)
Start indoors: Jan 9 Transplant: Feb 13 🍅 Harvest: May 8 – Jun 12
Recommended (50%) ✓ Fits season (151 days to spare)
Start indoors: Jan 27 Transplant: Mar 3 🍅 Harvest: May 26 – Jun 30
Safe Start (90%) ✓ Fits season (116 days to spare)
Start indoors: Mar 21 Transplant: Apr 25 🍅 Harvest: Jul 18 – Aug 22

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 Stanislaus County

How your county's soil matches Acorn Squash's growing requirements.

Soil pH

Your soil pH (6.5–7.7) is more alkaline than Acorn Squash prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Stanislaus County is excellent for Acorn Squash — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Acorn Squash.

How to Plant Acorn Squash

1"
Planting Depth
30"
Between Plants
42"
Between Rows

Succession Planting Acorn Squash

4
successive plantings in your 277-day season

Sow every 9.1 weeks. Last sowing by Aug 20 to harvest before frost.

Plant Water Budget

Plant needs
1.1″/week
Rainfall provides
0.2″/week
You supply
1.0″/week
Watering frequency 2-3 times/week
Season total 2,584 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Acorn Squash

Acorn Squash needs approximately 1.1 inches of water per week (4.8" per month). Here's how your county's rainfall compares month by month.

Month Acorn Squash Needs Rainfall You Supplement Action
Jan 3.1" 0" ❄️ Dormant
Feb 4.8" 3.5" 1.3" 💧 Light watering
Mar 4.8" 2.1" 2.7" 🚿 Regular watering
Apr 4.8" 1.3" 3.5" 🚿 Regular watering
May 4.8" 0.5" 4.3" 🚿 Regular watering
Jun 4.8" 0.1" 4.7" 🚿 Regular watering
Jul 4.8" 0" 4.8" 🚿 Regular watering
Aug 4.8" 0" 4.8" 🚿 Regular watering
Sep 4.8" 0.2" 4.6" 🚿 Regular watering
Oct 4.8" 0.7" 4.1" 🚿 Regular watering
Nov 4.8" 1.5" 3.3" 🚿 Regular watering
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Feb–Nov in Stanislaus County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Acorn Squash 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.

Acorn Squash needs ~1,845 GDD — county provides 5,699 GDD Excellent fit

Acorn Squash Planting Timeline — Stanislaus County, CA

Acorn Squash Planting Calendar

Activity When Date Range
Start Indoors January 27 Jan 27 – Feb 10
Transplant Outdoors March 3 Mar 3 – Mar 17
Direct Sow February 24 Feb 24 – Mar 17
Harvest May 26 May 26 – Jun 30

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.1"/week · 2-3 times/week

📅 Days to Maturity

80–100 days

🧪 Soil pH

Needs 5.5–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9b

📆 Growing Season

277 days in Stanislaus County

Growing Tips for Acorn Squash in Stanislaus County

Direct sow Acorn Squash outdoors after February 24 in Stanislaus County when soil has warmed and frost danger has passed.

Common pests for Acorn Squash in this region include squash vine borer and cucumber beetles. Use row covers early in the season and inspect plants weekly.

Stanislaus County receives only 15" of rain annually. Acorn Squash needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Acorn Squash in Stanislaus County, CA?

Stanislaus County is in Zone 9b with an average last frost of February 24. Plan your Acorn Squash planting based on this frost date — see the calendar above for exact timing.

What planting zone is Stanislaus County, CA?

Stanislaus County, California is in USDA Hardiness Zone 9b. The average last spring frost is February 24 and first fall frost is November 28.

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Your Stanislaus County Garden Planner — Free

A 24-page printable planner built for Stanislaus County (Zone 9b). 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 Stanislaus County, CA. Local conditions may vary. Last updated: May 2026.

Sources & credits

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