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When to Plant Acorn Squash in Adams County, IA

Adams County, Iowa Zone 5b May

What to do in May

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Adams County, Iowa.

Avg. last frost April 24
Avg. first frost October 11
Soil temp (4") 60°F
Watering Low
Pest pressure Low
Daylight 14.3 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. Seed acorn squash outdoors

    Succession planting is the secret here. Put in a row now, another in 2 weeks, a third in 4.

  3. Fire up the seed-starting tray: acorn squash

    Your window is short. These crops want several weeks of indoor growth before they go outside.

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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.

Adams County, Iowa is in USDA Zone 5b. The average last spring frost is April 24 and the first fall frost is October 11, giving you a growing season of approximately 170 days.

At an elevation of 998 feet, Adams County receives approximately 32.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Acorn Squash during the growing season.

Adams County, IA (Zone 5b) Moderate season
170 days
Last Spring Frost April 24
170 growing days
First Fall Frost October 11

Adams County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (37 days to spare)
Start indoors: Mar 14 Transplant: May 2 🍅 Harvest: Jul 25 – Aug 29
Recommended (50%) ✓ Fits season (37 days to spare)
Start indoors: Mar 20 Transplant: May 8 🍅 Harvest: Jul 31 – Sep 4
Safe Start (90%) ✓ Fits season (36 days to spare)
Start indoors: Apr 3 Transplant: May 22 🍅 Harvest: Aug 14 – Sep 18

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 Adams County

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

Soil pH

Your soil pH (6.1–7.2) overlaps with Acorn Squash's range (5.5–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Adams 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 170-day season

Sow every 9.1 weeks. Last sowing by Jul 03 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 557 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 1.4" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 4.8" 3.1" 1.7" 💧 Light watering
May 4.8" 4.3" 0.5" 💧 Light watering
Jun 4.8" 3.8" 1" 💧 Light watering
Jul 4.8" 3.4" 1.4" 💧 Light watering
Aug 4.8" 3.2" 1.6" 💧 Light watering
Sep 4.8" 2.9" 1.9" 💧 Light watering
Oct 4.8" 2.6" 2.2" 💧 Light watering
Nov 2" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Adams 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 ~1,305 GDD — county provides 2,465 GDD Excellent fit

Acorn Squash Planting Timeline — Adams County, IA

Acorn Squash Planting Calendar

Activity When Date Range
Start Indoors March 20 Mar 20 – Apr 3
Transplant Outdoors May 8 May 8 – May 22
Direct Sow May 1 May 1 – May 22
Harvest July 31 Jul 31 – Sep 4

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 Harvest
August Harvest
September Harvest
October
November
December

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: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

170 days in Adams County

Growing Tips for Acorn Squash in Adams County

Direct sow Acorn Squash outdoors after April 24 in Adams 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 Adams County, IA?

Adams County is in Zone 5b with an average last frost of April 24. Plan your Acorn Squash planting based on this frost date — see the calendar above for exact timing.

What planting zone is Adams County, IA?

Adams County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 24 and first fall frost is October 11.

🌱

Your Adams County Garden Planner — Free

A 24-page printable planner built for Adams County (Zone 5b). 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 Adams County, IA. Local conditions may vary. Last updated: May 2026.

Sources & credits

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