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When to Plant Pumpkin in La Plata County, CO

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

La Plata County, Colorado is in USDA Zone 5b. The average last spring frost is May 31 and the first fall frost is September 21, giving you a growing season of approximately 113 days.

At an elevation of 5,246 feet, La Plata County receives approximately 14.9 inches of rainfall annually with predominantly loam soil. Summer highs average 83ยฐF, 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.

La Plata County, CO (Zone 5b) Short season
113 days
Last Spring Frost May 31
113 growing days
First Fall Frost September 21

La Plata County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 9 Transplant: May 28 🍅 Harvest: Aug 27 – Oct 15
Recommended (50%) ✗ May not fit
Start indoors: Apr 26 Transplant: Jun 14 🍅 Harvest: Sep 13 – Nov 1
Safe Start (90%) ✗ May not fit
Start indoors: May 22 Transplant: Jul 10 🍅 Harvest: Oct 9 – Nov 27

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 La Plata County

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

Soil pH

Your soil pH (6.2โ€“7.9) overlaps with Pumpkin's range (6.0โ€“7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.7%). 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 901 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” 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 โ€” 0.9" 0" โ„๏ธ Dormant
Feb โ€” 0.9" 0" โ„๏ธ Dormant
Mar โ€” 1.2" 0" โ„๏ธ Dormant
Apr โ€” 1.6" 0" โ„๏ธ Dormant
May 5.6" 1.6" 4" ๐Ÿšฟ Regular watering
Jun 5.6" 0.9" 4.7" ๐Ÿšฟ Regular watering
Jul 5.6" 1.4" 4.2" ๐Ÿšฟ Regular watering
Aug 5.6" 1.5" 4.1" ๐Ÿšฟ Regular watering
Sep 5.6" 1.3" 4.3" ๐Ÿšฟ Regular watering
Oct โ€” 1.5" 0" โ„๏ธ Dormant
Nov โ€” 1" 0" โ„๏ธ Dormant
Dec โ€” 1" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in La Plata 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 ~1,256 GDD — county provides 1,384 GDD Good fit

Pumpkin Planting Timeline โ€” La Plata County, CO

Pumpkin Planting Calendar

Activity When Date Range
Start Indoors April 26 Apr 26 โ€“ May 10
Transplant Outdoors June 14 Jun 14 โ€“ Jun 28
Direct Sow June 7 Jun 7 โ€“ Jun 28
Harvest September 13 Sep 13 โ€“ Nov 1

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1.3"/week ยท 2-3 times/week

๐Ÿ“… Days to Maturity

85โ€“120 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 5b

๐Ÿ“† Growing Season

113 days in La Plata County

Growing Tips for Pumpkin in La Plata County

Direct sow Pumpkin outdoors after May 31 in La Plata County when soil has warmed and frost danger has passed.

Your 113.0-day growing season in La Plata 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.

La Plata County receives only 15" of rain annually. Pumpkin needs consistent moisture โ€” 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 La Plata County, CO?

La Plata County is in Zone 5b with an average last frost of May 31. Plan your Pumpkin planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is La Plata County, CO?

La Plata County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 31 and first fall frost is September 21.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help La Plata County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.

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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 La Plata County, CO. Local conditions may vary. Last updated: April 2026.