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When to Plant Pumpkin in Kossuth County, IA

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

Kossuth County, Iowa is in USDA Zone 4b. The average last spring frost is April 27 and the first fall frost is October 6, giving you a growing season of approximately 162 days.

At an elevation of 1,213 feet, Kossuth County receives approximately 36.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80ยฐF, so choose short-season varieties of Pumpkin to ensure they mature before fall.

Kossuth County, IA (Zone 4b) Moderate season
162 days
Last Spring Frost April 27
162 growing days
First Fall Frost October 6

Kossuth County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (3 days to spare)
Start indoors: Mar 10 Transplant: May 12 🍅 Harvest: Aug 11 – Sep 29
Recommended (50%) ✓ Fits season (1 days to spare)
Start indoors: Mar 16 Transplant: May 18 🍅 Harvest: Aug 17 – Oct 5
Safe Start (90%) ✓ Fits season (3 days to spare)
Start indoors: Mar 30 Transplant: Jun 1 🍅 Harvest: Aug 31 – Oct 19

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 Kossuth County

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

Soil pH

Your soil pH (6.2โ€“7.0) is within Pumpkin's preferred range (6.0โ€“7.5).

Soil Texture

The silt loam soil in Kossuth County is excellent for Pumpkin โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.9%) โ€” 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
1.0″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 510 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 โ€” 1.7" 0" โ„๏ธ Dormant
Feb โ€” 1.4" 0" โ„๏ธ Dormant
Mar โ€” 2.4" 0" โ„๏ธ Dormant
Apr 5.6" 3.8" 1.8" ๐Ÿ’ง Light watering
May 5.6" 3.7" 1.9" ๐Ÿ’ง Light watering
Jun 5.6" 5.1" 0.5" ๐Ÿ’ง Light watering
Jul 5.6" 4.3" 1.3" ๐Ÿ’ง Light watering
Aug 5.6" 3.7" 1.9" ๐Ÿ’ง Light watering
Sep 5.6" 2.9" 2.7" ๐Ÿ’ง Light watering
Oct 5.6" 3.2" 2.4" ๐Ÿ’ง Light watering
Nov โ€” 2.5" 0" โ„๏ธ Dormant
Dec โ€” 1.8" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Kossuth County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 1,620 GDD Excellent fit

Pumpkin Planting Timeline โ€” Kossuth County, IA

Pumpkin Planting Calendar

Activity When Date Range
Start Indoors March 16 Mar 16 โ€“ Mar 30
Transplant Outdoors May 18 May 18 โ€“ Jun 1
Direct Sow May 11 May 11 โ€“ Jun 1
Harvest August 17 Aug 17 โ€“ Oct 5

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April โ€”
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July โ€”
August Harvest
September Harvest
October Harvest
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1.3"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

85โ€“120 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 4b

๐Ÿ“† Growing Season

162 days in Kossuth County

Growing Tips for Pumpkin in Kossuth County

Direct sow Pumpkin outdoors after April 27 in Kossuth 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 Kossuth County, IA?

Kossuth County is in Zone 4b with an average last frost of April 27. Plan your Pumpkin planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Kossuth County, IA?

Kossuth County, Iowa is in USDA Hardiness Zone 4b. The average last spring frost is April 27 and first fall frost is October 6.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Kossuth County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Kossuth County, IA. Local conditions may vary. Last updated: April 2026.