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When to Plant Acorn Squash in Buffalo County, WI

Buffalo County, Wisconsin Zone 4b May

Top priorities for Buffalo County, Wisconsin gardeners in May

We've pulled the most time-sensitive tasks for Buffalo County, Wisconsin this May and put them front and centre. Tackle them in order.

Avg. last frost May 12
Avg. first frost September 30
Soil temp (4") 56°F
Watering Low
Pest pressure Low
Daylight 14.6 hrs
  1. Put acorn squash seeds straight in the ground

    Sow every 2 weeks for a continuous harvest. A single big planting means a single big glut.

Looking ahead to June
  • 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.

Buffalo County, Wisconsin is in USDA Zone 4b. 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 661 feet, Buffalo County receives approximately 36.4 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.

Buffalo County, WI (Zone 4b) Short season
141 days
Last Spring Frost May 12
141 growing days
First Fall Frost September 30

Buffalo County Soil Profile

Soil Type

Silt Loam

Soil pH

6-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (5 days to spare)
Start indoors: Mar 21 Transplant: May 23 🍅 Harvest: Aug 15 – Sep 19
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 (6 days to spare)
Start indoors: Apr 8 Transplant: Jun 10 🍅 Harvest: Sep 2 – Oct 7

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 Buffalo County

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

Soil pH

Your soil pH (6.0–6.9) is within Acorn Squash's preferred range (5.5–7.0).

Soil Texture

The silt loam soil in Buffalo 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

Plant Water Budget

Plant needs
1.1″/week
Rainfall provides
1.1″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 24 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 1.4" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 3.8" 0" ❄️ Dormant
May 4.8" 4.5" 0.3" 💧 Light watering
Jun 4.8" 4.6" 0.2" 💧 Light watering
Jul 4.8" 3.8" 1" 💧 Light watering
Aug 4.8" 3.6" 1.2" 💧 Light watering
Sep 4.8" 3.5" 1.3" 💧 Light watering
Oct 2.8" 0" ❄️ Dormant
Nov 2.2" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Buffalo 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 1,410 GDD Excellent fit

Acorn Squash Planting Timeline — Buffalo County, WI

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 · Only during dry spells

📅 Days to Maturity

80–100 days

🧪 Soil pH

Needs 5.5–7 · Your soil: ideal

🗺️ USDA Zone

Zone 4b

📆 Growing Season

141 days in Buffalo County

Growing Tips for Acorn Squash in Buffalo County

Direct sow Acorn Squash outdoors after May 12 in Buffalo 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 Buffalo County, WI?

Buffalo County is in Zone 4b 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 Buffalo County, WI?

Buffalo County, Wisconsin is in USDA Hardiness Zone 4b. The average last spring frost is May 12 and first fall frost is September 30.

🌱

Your Buffalo County Garden Planner — Free

A 24-page printable planner built for Buffalo County (Zone 4b). 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 Buffalo County, WI. 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.