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When to plant Pumpkin in Cass County, MN

Plant Pumpkin in Cass County during the brief May 26–June 16 window. With 139 frost-free days, fall plantings can't mature before September 28.

When to Plant Pumpkin in Cass County, MN

Pumpkin
Cass County, Minnesota Zone 4a June

Your June planting checklist for Cass County, Minnesota

Your garden in Cass County, Minnesota is working on a schedule, even when you're not. Here's where you should be this June.

Avg. last frost May 12
Avg. first frost September 28
Soil temp (4") 61°F
Watering Low
Pest pressure Moderate
Daylight 15.7 hrs
  1. Plant out pumpkin

    Frost risk is low now in Cass County, Minnesota. If you've been covering beds overnight, you can stop.

  2. Time to start pumpkin inside

    Label every cell. You will absolutely forget which is which otherwise.

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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.

Cass County, Minnesota is in USDA Zone 4a. The average last spring frost is May 12 and the first fall frost is September 28, giving you a growing season of approximately 139 days.

At an elevation of 938 feet, Cass County receives approximately 32.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Pumpkin to ensure they mature before fall.

Cass County, MN (Zone 4a) Short season
139 days
Last Spring Frost May 12
139 growing days
First Fall Frost September 28

Cass County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.9

Drainage

Well Drained

Pumpkin Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 27 Transplant: May 29 🍅 Harvest: Aug 28 – Oct 16
Recommended (50%) ✗ May not fit
Start indoors: Mar 31 Transplant: Jun 2 🍅 Harvest: Sep 1 – Oct 20
Safe Start (90%) ✗ May not fit
Start indoors: Apr 15 Transplant: Jun 17 🍅 Harvest: Sep 16 – Nov 4

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 Cass County

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

Soil pH

Your soil pH (5.9–6.9) overlaps with Pumpkin's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.6%) — Pumpkin will thrive.

How to Plant Pumpkin

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

Pumpkin Water Budget

Plant needs
1.3″/week
Rainfall provides
1.0″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 397 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 1.3" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 3" 0" ❄️ Dormant
May 5.6" 3.5" 2.1" 💧 Light watering
Jun 5.6" 3.9" 1.7" 💧 Light watering
Jul 5.6" 3.8" 1.8" 💧 Light watering
Aug 5.6" 3.5" 2.1" 💧 Light watering
Sep 5.6" 3.2" 2.4" 💧 Light watering
Oct 2.5" 0" ❄️ Dormant
Nov 2.2" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Cass 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 ~1,025 GDD — county provides 1,390 GDD Excellent fit

Pumpkin Planting Timeline — Cass County, MN

Pumpkin 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 September 1 Sep 1 – Oct 20

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
September Harvest
October Harvest
November
December

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: acceptable

🗺️ USDA Zone

Zone 4a

📆 Growing Season

139 days in Cass County

Growing Tips for Pumpkin in Cass County

Direct sow Pumpkin outdoors after May 12 in Cass 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 Cass County, MN?

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

What planting zone is Cass County, MN?

Cass County, Minnesota is in USDA Hardiness Zone 4a. The average last spring frost is May 12 and first fall frost is September 28.

When should I plant Pumpkin in Cass County, MN?

In Cass County, MN, plant Pumpkin after the last frost (around May 12) and before the first frost (around September 28). Best results when soil holds above 50°F.

What growing zone is Cass County, MN for Pumpkin?

Cass County sits in USDA Zone 4a. Pumpkin grows reliably in zones 3a through 10b, so it's a good fit here.

Can Pumpkin grow in Cass County's climate?

Yes — Pumpkin grows well in Cass County's temperate climate. Cass County averages a 139-day frost-free season, with last frost around May 12 and first frost around September 28.

🌱

Your Cass County Garden Planner — Free

A 22-page printable planner built for Cass 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 Cass County, MN. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.