Blog

When to Plant Pumpkin in Washburn County, WI

Washburn County, Wisconsin Zone 4a May

This month in Washburn County, Wisconsin

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

Avg. last frost May 17
Avg. first frost September 25
Soil temp (4") 50°F
Watering Moderate
Pest pressure Low
Daylight 14.7 hrs
  1. Plant pumpkin from seed, right in the garden

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

To set up a strong June, finish these tasks
  • Transplants going out: pumpkin
  • Starting indoors: pumpkin

Instant PDF download. No spam, unsubscribe any time.

Pumpkins are large-fruited squash varieties grown for eating, decoration, and seed production. They require ample space and a long, warm growing season.

Washburn County, Wisconsin is in USDA Zone 4a. The average last spring frost is May 17 and the first fall frost is September 25, giving you a growing season of approximately 131 days.

At an elevation of 954 feet, Washburn County receives approximately 32.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 79°F, so choose short-season varieties of Pumpkin to ensure they mature before fall.

Washburn County, WI (Zone 4a) Short season
131 days
Last Spring Frost May 17
131 growing days
First Fall Frost September 25
Share this guide:

Washburn County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 2 Transplant: Jun 4 🍅 Harvest: Sep 3 – Oct 22
Recommended (50%) ✗ May not fit
Start indoors: Apr 5 Transplant: Jun 7 🍅 Harvest: Sep 6 – Oct 25
Safe Start (90%) ✗ May not fit
Start indoors: Apr 20 Transplant: Jun 22 🍅 Harvest: Sep 21 – Nov 9

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 Washburn County

How your county's soil matches Pumpkin's growing requirements.

Soil pH

Your soil pH (6.1–6.9) is within Pumpkin's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

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

How to Plant Pumpkin

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

Plant Water Budget

Plant needs
1.3″/week
Rainfall provides
1.1″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 352 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Pumpkin

Pumpkin needs approximately 1.3 inches of water per week (5.6" per month). Here's how your county's rainfall compares month by month.

Month Pumpkin Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 3.5" 0" ❄️ Dormant
May 5.6" 3.7" 1.9" 💧 Light watering
Jun 5.6" 3.6" 2" 💧 Light watering
Jul 5.6" 4" 1.6" 💧 Light watering
Aug 5.6" 3.6" 2" 💧 Light watering
Sep 5.6" 3.1" 2.5" 💧 Light watering
Oct 2.7" 0" ❄️ Dormant
Nov 2.1" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

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

Pumpkin 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.

Pumpkin needs ~948 GDD — county provides 1,211 GDD Good fit

Pumpkin Planting Timeline — Washburn County, WI

Pumpkin Planting Calendar

Activity When Date Range
Start Indoors April 5 Apr 5 – Apr 19
Transplant Outdoors June 7 Jun 7 – Jun 21
Direct Sow May 31 May 31 – Jun 21
Harvest September 6 Sep 6 – Oct 25

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Direct Sow
June Transplant Outdoors Direct Sow
July
August
September Harvest
October Harvest
November
December
Share this guide:

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.3"/week · 1-2 times/week

📅 Days to Maturity

85–120 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 4a

📆 Growing Season

131 days in Washburn County

Growing Tips for Pumpkin in Washburn County

Direct sow Pumpkin outdoors after May 17 in Washburn County when soil has warmed and frost danger has passed.

Your 131.0-day growing season in Washburn County is tight for Pumpkin (85.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.

Common pests for Pumpkin 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 on mounds after last frost. Allow 6-10 feet between plants. Slip a board under developing fruit to prevent rot. Harvest when rind is hard and deep in color.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Pumpkin in Washburn County, WI?

Washburn County is in Zone 4a with an average last frost of May 17. Plan your Pumpkin planting based on this frost date — see the calendar above for exact timing.

What planting zone is Washburn County, WI?

Washburn County, Wisconsin is in USDA Hardiness Zone 4a. The average last spring frost is May 17 and first fall frost is September 25.

🌱

Your Washburn County Garden Planner — Free

A 24-page printable planner built for Washburn 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.

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 Washburn 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.