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When to Plant Acorn Squash in Sac County, IA

Sac County, Iowa Zone 5a May

Top priorities for Sac County, Iowa gardeners in May

Your garden in Sac County, Iowa is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost April 25
Avg. first frost October 8
Soil temp (4") 54°F
Watering Moderate
Pest pressure Low
Daylight 14.4 hrs
  1. Time to transplant acorn squash

    Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.

  2. Scatter acorn squash into prepared beds

    Rake a smooth bed, make a shallow furrow, drop seeds at the spacing on the packet, water gently, walk away.

  3. Start acorn squash indoors

    These need a head start before your last frost (April 25). Sow into cells now so you're ready to transplant in a few weeks.

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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.

Sac County, Iowa is in USDA Zone 5a. The average last spring frost is April 25 and the first fall frost is October 8, giving you a growing season of approximately 166 days.

At an elevation of 1,221 feet, Sac County receives approximately 31.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Acorn Squash to ensure they mature before fall.

Sac County, IA (Zone 5a) Moderate season
166 days
Last Spring Frost April 25
166 growing days
First Fall Frost October 8
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Sac County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (32 days to spare)
Start indoors: Mar 17 Transplant: May 5 🍅 Harvest: Jul 28 – Sep 1
Recommended (50%) ✓ Fits season (33 days to spare)
Start indoors: Mar 21 Transplant: May 9 🍅 Harvest: Aug 1 – Sep 5
Safe Start (90%) ✓ Fits season (31 days to spare)
Start indoors: Apr 5 Transplant: May 24 🍅 Harvest: Aug 16 – Sep 20

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 Sac County

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

Soil pH

Your soil pH (5.9–6.7) is within Acorn Squash's preferred range (5.5–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.8%) — Acorn Squash will thrive.

How to Plant Acorn Squash

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

Succession Planting Acorn Squash

2
successive plantings in your 166-day season

Sow every 9.1 weeks. Last sowing by Jun 30 to harvest before frost.

Plant Water Budget

Plant needs
1.1″/week
Rainfall provides
0.8″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 542 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 1.3" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 4.8" 3.4" 1.4" 💧 Light watering
May 4.8" 3.6" 1.2" 💧 Light watering
Jun 4.8" 3.4" 1.4" 💧 Light watering
Jul 4.8" 3.4" 1.4" 💧 Light watering
Aug 4.8" 3.2" 1.6" 💧 Light watering
Sep 4.8" 2.7" 2.1" 💧 Light watering
Oct 4.8" 2.6" 2.2" 💧 Light watering
Nov 2.5" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Sac 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 ~900 GDD — county provides 1,660 GDD Excellent fit

Acorn Squash Planting Timeline — Sac County, IA

Acorn Squash Planting Calendar

Activity When Date Range
Start Indoors March 21 Mar 21 – Apr 4
Transplant Outdoors May 9 May 9 – May 23
Direct Sow May 2 May 2 – May 23
Harvest August 1 Aug 1 – Sep 5

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.1"/week · 1-2 times/week

📅 Days to Maturity

80–100 days

🧪 Soil pH

Needs 5.5–7 · Your soil: ideal

🗺️ USDA Zone

Zone 5a

📆 Growing Season

166 days in Sac County

Growing Tips for Acorn Squash in Sac County

Direct sow Acorn Squash outdoors after April 25 in Sac 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.

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 Sac County, IA?

Sac County is in Zone 5a with an average last frost of April 25. Plan your Acorn Squash planting based on this frost date — see the calendar above for exact timing.

What planting zone is Sac County, IA?

Sac County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 25 and first fall frost is October 8.

🌱

Your Sac County Garden Planner — Free

A 24-page printable planner built for Sac County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Sac County, IA. 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.