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When to Plant Pumpkin in Park County, WY

Park County, Wyoming Zone 5a May

May to-do list for Park County, Wyoming

Here's what deserves your attention in Park County, Wyoming this month. Everything below is tailored to Zone 5a and timed around your local frost dates.

Avg. last frost May 21
Avg. first frost September 22
Soil temp (4") 34°F
Watering High
Pest pressure Low
Daylight 14.6 hrs
  1. Seed pumpkin outdoors

    Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.

Coming up in June — start thinking about
  • 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.

Park County, Wyoming is in USDA Zone 5a. The average last spring frost is May 21 and the first fall frost is September 22, giving you a growing season of approximately 124 days.

At an elevation of 6,993 feet, Park County receives approximately 16.7 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Pumpkin to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Pumpkin successfully. Mulch heavily to conserve soil moisture.

Park County, WY (Zone 5a) Short season
124 days
Last Spring Frost May 21
124 growing days
First Fall Frost September 22

Park County Soil Profile

Soil Type

Loam

Soil pH

6.8-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 5 Transplant: May 24 🍅 Harvest: Aug 23 – Oct 11
Recommended (50%) ✗ May not fit
Start indoors: Apr 16 Transplant: Jun 4 🍅 Harvest: Sep 3 – Oct 22
Safe Start (90%) ✗ May not fit
Start indoors: May 24 Transplant: Jul 12 🍅 Harvest: Oct 11 – Nov 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 Park County

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

Soil pH

Your soil pH (6.8–8.2) overlaps with Pumpkin's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). 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
0.6″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 973 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 1.3" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1.3" 0" ❄️ Dormant
Apr 1.8" 0" ❄️ Dormant
May 5.6" 2.1" 3.5" 🚿 Regular watering
Jun 5.6" 1.2" 4.4" 🚿 Regular watering
Jul 5.6" 1.5" 4.1" 🚿 Regular watering
Aug 5.6" 1.7" 3.9" 🚿 Regular watering
Sep 5.6" 1.2" 4.4" 🚿 Regular watering
Oct 1.4" 0" ❄️ Dormant
Nov 1.3" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Park 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 ~1,256 GDD — county provides 1,519 GDD Good fit

Pumpkin Planting Timeline — Park County, WY

Pumpkin Planting Calendar

Activity When Date Range
Start Indoors April 16 Apr 16 – Apr 30
Transplant Outdoors June 4 Jun 4 – Jun 18
Direct Sow May 28 May 28 – Jun 18
Harvest September 3 Sep 3 – Oct 22

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 · 2-3 times/week

📅 Days to Maturity

85–120 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

124 days in Park County

Growing Tips for Pumpkin in Park County

Direct sow Pumpkin outdoors after May 21 in Park County when soil has warmed and frost danger has passed.

Your 124.0-day growing season in Park 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.

Park County receives only 17" of rain annually. Pumpkin needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Park County, WY?

Park County is in Zone 5a with an average last frost of May 21. Plan your Pumpkin planting based on this frost date — see the calendar above for exact timing.

What planting zone is Park County, WY?

Park County, Wyoming is in USDA Hardiness Zone 5a. The average last spring frost is May 21 and first fall frost is September 22.

🌱

Your Park County Garden Planner — Free

A 24-page printable planner built for Park County (Zone 5a). 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 Park County, WY. 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.