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When to Plant Butternut Squash in Delta County, CO

Butternut squash is a popular winter squash with a long neck, small seed cavity, and sweet, nutty orange flesh. It stores exceptionally well for months.

Delta County, Colorado is in USDA Zone 6a. The average last spring frost is May 1 and the first fall frost is October 8, giving you a growing season of approximately 160 days.

At an elevation of 4,470 feet, Delta County receives approximately 13.4 inches of rainfall annually with predominantly loam soil. Summer highs average 87ยฐF, providing good warmth for Butternut Squash during the growing season. With low rainfall, drip irrigation is essential for growing Butternut Squash successfully. Mulch heavily to conserve soil moisture.

Delta County, CO (Zone 6a) Moderate season
160 days
Last Spring Frost May 1
160 growing days
First Fall Frost October 8

Delta County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (25 days to spare)
Start indoors: Mar 18 Transplant: May 6 🍅 Harvest: Aug 5 – Sep 9
Recommended (50%) ✓ Fits season (20 days to spare)
Start indoors: Mar 27 Transplant: May 15 🍅 Harvest: Aug 14 – Sep 18
Safe Start (90%) ✓ Fits season (21 days to spare)
Start indoors: Apr 12 Transplant: May 31 🍅 Harvest: Aug 30 – Oct 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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.4″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 1,108 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Butternut Squash needs ~1,487 GDD — county provides 2,440 GDD Excellent fit

Butternut Squash Planting Timeline โ€” Delta County, CO

Butternut Squash Planting Calendar

Activity When Date Range
Start Indoors March 27 Mar 27 โ€“ Apr 10
Transplant Outdoors May 15 May 15 โ€“ May 29
Direct Sow May 8 May 8 โ€“ May 29
Harvest August 14 Aug 14 โ€“ Sep 18

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

85โ€“110 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 6a

Growing Season

160 days

Growing Tips for Delta County

Start seeds indoors 3 weeks early or direct sow after frost. Allow 6-8 feet for sprawling vines. Harvest when the skin is hard and uniformly tan. Cure in the sun for 10 days.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Level Up Your Garden

Frequently Asked Questions

When should I plant Butternut Squash in Delta County, CO?

Delta County is in Zone 6a with an average last frost of May 1. Plan your Butternut Squash planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Delta County, CO?

Delta County, Colorado is in USDA Hardiness Zone 6a. The average last spring frost is May 1 and first fall frost is October 8.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Delta County gardeners in Zone 6a 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 Delta County, CO. Local conditions may vary. Last updated: April 2026.