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When to plant Butternut Squash in Pullman, MI

Butternut Squash planted in Pullman between May 9 and May 30 matures in 110 days — well before the October 14 first frost.

When to Plant Butternut Squash in Pullman, MI

Allegan County, Michigan Zone 6a June

What to do in June

June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Allegan County, Michigan.

Avg. last frost May 2
Avg. first frost October 14
Soil temp (4") 70°F
Watering Low
Pest pressure High
Daylight 15.1 hrs

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Butternut squash is a popular winter squash with a long neck, small seed cavity, and sweet, nutty orange flesh. It stores exceptionally well for months.

Pullman, Michigan is in USDA Zone 6a. The average last spring frost is May 2 and the first fall frost is October 14, giving you a growing season of approximately 165 days.

At an elevation of 1,257 feet, Allegan County receives approximately 37.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Butternut Squash during the growing season.

Pullman, MI (Zone 6a) Moderate season
165 days
Last Spring Frost May 2
165 growing days
First Fall Frost October 14

Pullman Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.7

Drainage

Well Drained

Butternut Squash Planting Risk Windows

Early Start (70% safe) ✓ Fits season (24 days to spare)
Start indoors: Mar 23 Transplant: May 11 🍅 Harvest: Aug 10 – Sep 14
Recommended (50%) ✓ Fits season (25 days to spare)
Start indoors: Mar 28 Transplant: May 16 🍅 Harvest: Aug 15 – Sep 19
Safe Start (90%) ✓ Fits season (18 days to spare)
Start indoors: Apr 16 Transplant: Jun 4 🍅 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 Pullman

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

Soil pH

Your soil pH (6.2–6.7) is within Butternut Squash's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.3%) — Butternut Squash will thrive.

How to Plant Butternut Squash

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

Butternut Squash Water Budget

Plant needs
1.1″/week
Rainfall provides
1.0″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 214 gal / 100 sq ft

Monthly Watering Guide for Butternut Squash

Butternut 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 Butternut Squash Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 3.8" 0" ❄️ Dormant
May 4.8" 3.5" 1.3" 💧 Light watering
Jun 4.8" 4.9" 0" ✅ Rainfall sufficient
Jul 4.8" 4.2" 0.6" 💧 Light watering
Aug 4.8" 3.4" 1.4" 💧 Light watering
Sep 4.8" 3.6" 1.2" 💧 Light watering
Oct 4.8" 3.1" 1.7" 💧 Light watering
Nov 2.8" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

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

Butternut 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.

Butternut Squash needs ~1,414 GDD — county provides 2,392 GDD Excellent fit

Butternut Squash Planting Timeline — Pullman, MI

Butternut Squash Planting Calendar

Activity When Date Range
Start Indoors March 28 Mar 28 – Apr 11
Transplant Outdoors May 16 May 16 – May 30
Direct Sow May 9 May 9 – May 30
Harvest August 15 Aug 15 – Sep 19

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.1"/week · Only during dry spells

📅 Days to Maturity

85–110 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

165 days in Allegan County

Growing Tips for Butternut Squash in Pullman

Direct sow Butternut Squash outdoors after May 02 in Allegan County when soil has warmed and frost danger has passed.

Common pests for Butternut 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

Start seeds indoors 3 weeks early or direct sow after frost. Allow 6-8 feet for sprawling vines. Harvest when the skin is hard and uniformly tan. Cure in the sun for 10 days.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

When should I plant Butternut Squash in Pullman, MI?

In Pullman, MI, plant Butternut Squash after the last frost (around May 2) and before the first frost (around October 14). Best results when soil holds above 50°F.

What growing zone is Pullman, MI for Butternut Squash?

Pullman sits in USDA Zone 6a. Butternut Squash grows reliably in zones 3a through 11b, so it's a good fit here.

Can Butternut Squash grow in Pullman's climate?

Yes — Butternut Squash grows well in Pullman's temperate climate. Pullman averages a 165-day frost-free season, with last frost around May 2 and first frost around October 14.

🌱

Your Allegan County Garden Planner — Free

A 22-page printable planner built for Allegan County (Zone 6a). 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 Allegan County, MI. Local conditions may vary. Last updated: June 2026.