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When to Plant Pumpkin in Clark County, WI

Clark County, Wisconsin Zone 4b May

This month in Clark County, Wisconsin

May is a pivotal month for Clark County, Wisconsin gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 13
Avg. first frost September 30
Soil temp (4") 54°F
Watering Low
Pest pressure Low
Daylight 14.6 hrs
  1. Sow pumpkin where they'll grow

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

Get ahead of June
  • Transplants going out: pumpkin
  • Starting indoors: pumpkin

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

Clark County, Wisconsin is in USDA Zone 4b. The average last spring frost is May 13 and the first fall frost is September 30, giving you a growing season of approximately 140 days.

At an elevation of 850 feet, Clark County receives approximately 39.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82°F, so choose short-season varieties of Pumpkin to ensure they mature before fall.

Clark County, WI (Zone 4b) Short season
140 days
Last Spring Frost May 13
140 growing days
First Fall Frost September 30

Clark County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 24 Transplant: May 26 🍅 Harvest: Aug 25 – Oct 13
Recommended (50%) ✗ May not fit
Start indoors: Apr 1 Transplant: Jun 3 🍅 Harvest: Sep 2 – Oct 21
Safe Start (90%) ✗ May not fit
Start indoors: Apr 9 Transplant: Jun 11 🍅 Harvest: Sep 10 – Oct 29

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 Clark County

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

Soil pH

Your soil pH (6.1–6.8) is within Pumpkin's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Pumpkin.

How to Plant Pumpkin

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

Plant Water Budget

Plant needs
1.3″/week
Rainfall provides
1.2″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 132 gal / 100 sq ft

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 1.8" 0" ❄️ Dormant
Feb 2" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 3.9" 0" ❄️ Dormant
May 5.6" 4.6" 1" 💧 Light watering
Jun 5.6" 4.6" 1" 💧 Light watering
Jul 5.6" 4.2" 1.4" 💧 Light watering
Aug 5.6" 4.2" 1.4" 💧 Light watering
Sep 5.6" 3.7" 1.9" 💧 Light watering
Oct 2.8" 0" ❄️ Dormant
Nov 3" 0" ❄️ Dormant
Dec 2.4" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Clark 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 ~1,179 GDD — county provides 1,610 GDD Excellent fit

Pumpkin Planting Timeline — Clark County, WI

Pumpkin Planting Calendar

Activity When Date Range
Start Indoors April 1 Apr 1 – Apr 15
Transplant Outdoors June 3 Jun 3 – Jun 17
Direct Sow May 27 May 27 – Jun 17
Harvest September 2 Sep 2 – Oct 21

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.3"/week · Only during dry spells

📅 Days to Maturity

85–120 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 4b

📆 Growing Season

140 days in Clark County

Growing Tips for Pumpkin in Clark County

Direct sow Pumpkin outdoors after May 13 in Clark County when soil has warmed and frost danger has passed.

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 Clark County, WI?

Clark County is in Zone 4b with an average last frost of May 13. Plan your Pumpkin planting based on this frost date — see the calendar above for exact timing.

What planting zone is Clark County, WI?

Clark County, Wisconsin is in USDA Hardiness Zone 4b. The average last spring frost is May 13 and first fall frost is September 30.

🌱

Your Clark County Garden Planner — Free

A 24-page printable planner built for Clark 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.

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 Clark 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.