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When to Plant Acorn Squash in McLean County, ND

McLean County, North Dakota Zone 4a May

This month in McLean County, North Dakota

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

Avg. last frost May 12
Avg. first frost September 30
Soil temp (4") 54°F
Watering High
Pest pressure Low
Daylight 14.9 hrs
  1. Sow acorn squash where they'll grow

    Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.

Before June arrives, get these ready
  • Transplants going out: acorn squash
  • Starting indoors: 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.

McLean County, North Dakota is in USDA Zone 4a. The average last spring frost is May 12 and the first fall frost is September 30, giving you a growing season of approximately 141 days.

At an elevation of 1,071 feet, McLean County receives approximately 21.5 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Acorn Squash to ensure they mature before fall.

McLean County, ND (Zone 4a) Short season
141 days
Last Spring Frost May 12
141 growing days
First Fall Frost September 30

McLean County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (1 days to spare)
Start indoors: Mar 23 Transplant: May 25 🍅 Harvest: Aug 17 – Sep 21
Recommended (50%) ✓ Fits season (1 days to spare)
Start indoors: Mar 31 Transplant: Jun 2 🍅 Harvest: Aug 25 – Sep 29
Safe Start (90%) ✓ Fits season (4 days to spare)
Start indoors: Apr 9 Transplant: Jun 11 🍅 Harvest: Sep 3 – Oct 8

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 McLean County

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

Soil pH

Your soil pH (6.6–7.8) 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 McLean County is excellent for Acorn Squash — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.5%). Annual compost additions will help Acorn Squash.

How to Plant Acorn Squash

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

Plant Water Budget

Plant needs
1.1″/week
Rainfall provides
0.6″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 692 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 1.5" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2.4" 0" ❄️ Dormant
May 4.8" 2.5" 2.3" 💧 Light watering
Jun 4.8" 1.5" 3.3" 🚿 Regular watering
Jul 4.8" 1.9" 2.9" 🚿 Regular watering
Aug 4.8" 2.4" 2.4" 🚿 Regular watering
Sep 4.8" 1.8" 3" 🚿 Regular watering
Oct 1.9" 0" ❄️ Dormant
Nov 1.3" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in McLean 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 ~1,035 GDD — county provides 1,621 GDD Excellent fit

Acorn Squash Planting Timeline — McLean County, ND

Acorn Squash Planting Calendar

Activity When Date Range
Start Indoors March 31 Mar 31 – Apr 14
Transplant Outdoors June 2 Jun 2 – Jun 16
Direct Sow May 26 May 26 – Jun 16
Harvest August 25 Aug 25 – Sep 29

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors
May Direct Sow
June Transplant Outdoors Direct Sow
July
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: too_alkaline

🗺️ USDA Zone

Zone 4a

📆 Growing Season

141 days in McLean County

Growing Tips for Acorn Squash in McLean County

Direct sow Acorn Squash outdoors after May 12 in McLean 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.

McLean County receives only 22" 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 McLean County, ND?

McLean County is in Zone 4a with an average last frost of May 12. Plan your Acorn Squash planting based on this frost date — see the calendar above for exact timing.

What planting zone is McLean County, ND?

McLean County, North Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 12 and first fall frost is September 30.

🌱

Your McLean County Garden Planner — Free

A 24-page printable planner built for McLean County (Zone 4a). 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 McLean County, ND. 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.