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When to Plant Pumpkin in Clear Creek County, CO

Clear Creek County, Colorado Zone 5a May

May in the garden — Clear Creek County, Colorado

Welcome to May in Zone 5a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 14
Avg. first frost September 26
Soil temp (4") 35°F
Watering High
Pest pressure Low
Daylight 14.2 hrs
  1. Harden off and plant pumpkin

    Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.

  2. Outdoor sowing time: pumpkin

    Rake a smooth bed, make a shallow furrow, drop seeds at the spacing on the packet, water gently, walk away.

To set up a strong June, finish these tasks
  • 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.

Clear Creek County, Colorado is in USDA Zone 5a. The average last spring frost is May 14 and the first fall frost is September 26, giving you a growing season of approximately 135 days.

At an elevation of 6,538 feet, Clear Creek County receives approximately 24.6 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.

Clear Creek County, CO (Zone 5a) Short season
135 days
Last Spring Frost May 14
135 growing days
First Fall Frost September 26
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Clear Creek County Soil Profile

Soil Type

Loam

Soil pH

6.8-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 29 Transplant: May 17 🍅 Harvest: Aug 16 – Oct 4
Recommended (50%) ✗ May not fit
Start indoors: Apr 9 Transplant: May 28 🍅 Harvest: Aug 27 – Oct 15
Safe Start (90%) ✗ May not fit
Start indoors: May 6 Transplant: Jun 24 🍅 Harvest: Sep 23 – Nov 11

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 Clear Creek County

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

Soil pH

Your soil pH (6.8–8.1) overlaps with Pumpkin's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.2%). 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
0.8″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 771 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 1.9" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2.7" 0" ❄️ Dormant
May 5.6" 2.7" 2.9" 🚿 Regular watering
Jun 5.6" 1.7" 3.9" 🚿 Regular watering
Jul 5.6" 2.4" 3.2" 🚿 Regular watering
Aug 5.6" 2.4" 3.2" 🚿 Regular watering
Sep 5.6" 2.1" 3.5" 🚿 Regular watering
Oct 2.3" 0" ❄️ Dormant
Nov 1.9" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Clear Creek 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 1,653 GDD Excellent fit

Pumpkin Planting Timeline — Clear Creek County, CO

Pumpkin Planting Calendar

Activity When Date Range
Start Indoors April 9 Apr 9 – Apr 23
Transplant Outdoors May 28 May 28 – Jun 11
Direct Sow May 21 May 21 – Jun 11
Harvest August 27 Aug 27 – Oct 15

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July
August Harvest
September Harvest
October Harvest
November
December
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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 5a

📆 Growing Season

135 days in Clear Creek County

Growing Tips for Pumpkin in Clear Creek County

Direct sow Pumpkin outdoors after May 14 in Clear Creek 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.

Clear Creek County receives only 25" 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 Clear Creek County, CO?

Clear Creek County is in Zone 5a with an average last frost of May 14. Plan your Pumpkin planting based on this frost date — see the calendar above for exact timing.

What planting zone is Clear Creek County, CO?

Clear Creek County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is May 14 and first fall frost is September 26.

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Your Clear Creek County Garden Planner — Free

A 24-page printable planner built for Clear Creek 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 Clear Creek County, CO. 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.