When to Plant Butternut Squash in Weld 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.
Weld County, Colorado is in USDA Zone 5a. The average last spring frost is May 2 and the first fall frost is October 7, giving you a growing season of approximately 158 days.
At an elevation of 6,992 feet, Weld County receives approximately 18.8 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, 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.
Weld County Soil Profile
Soil Type
Loam
Soil pH
6.6-8.1
Drainage
Well Drained
Plant Planting Risk Windows
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 Weld County
How your county's soil matches Butternut Squash's growing requirements.
Soil pH
Your soil pH (6.6–8.1) is more alkaline than Butternut Squash prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Weld County is excellent for Butternut Squash — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.2%). Annual compost additions will help Butternut Squash.
How to Plant Butternut Squash
Plant Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Butternut Squash
Butternut Squash needs approximately 1.1 inches of water per week (4.8" per month). Here's how your county's rainfall compares month by month.
| Month | Butternut Squash Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.4" | 0" | ❄️ Dormant |
| Feb | — | 1" | 0" | ❄️ Dormant |
| Mar | — | 1.5" | 0" | ❄️ Dormant |
| Apr | — | 2.1" | 0" | ❄️ Dormant |
| May | 4.8" | 2.3" | 2.5" | 🚿 Regular watering |
| Jun | 4.8" | 1.4" | 3.4" | 🚿 Regular watering |
| Jul | 4.8" | 1.7" | 3.1" | 🚿 Regular watering |
| Aug | 4.8" | 1.8" | 3" | 🚿 Regular watering |
| Sep | 4.8" | 1.7" | 3.1" | 🚿 Regular watering |
| Oct | 4.8" | 1.7" | 3.1" | 🚿 Regular watering |
| Nov | — | 1.2" | 0" | ❄️ Dormant |
| Dec | — | 1.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Weld County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Butternut Squash 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.
Butternut Squash Planting Timeline — Weld County, CO
Butternut Squash Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 28 | Mar 28 – Apr 11 |
| Transplant Outdoors | May 16 | May 16 – May 30 |
| Direct Sow | May 9 | May 9 – May 30 |
| Harvest | August 15 | Aug 15 – Sep 19 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | — |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.1"/week · 2-3 times/week
📅 Days to Maturity
85–110 days
🧪 Soil pH
Needs 6–7 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 5a
📆 Growing Season
158 days in Weld County
Growing Tips for Butternut Squash in Weld County
Direct sow Butternut Squash outdoors after May 02 in Weld County when soil has warmed and frost danger has passed.
Common pests for Butternut Squash in this region include squash vine borer and cucumber beetles. Use row covers early in the season and inspect plants weekly.
Weld County receives only 19" of rain annually. Butternut Squash needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
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
Check more plant combinations with our Companion Planting Checker →
Butternut Squash in Other Locations
Frequently Asked Questions
When should I plant Butternut Squash in Weld County, CO?
Weld County is in Zone 5a with an average last frost of May 2. Plan your Butternut Squash planting based on this frost date — see the calendar above for exact timing.
What planting zone is Weld County, CO?
Weld County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is May 2 and first fall frost is October 7.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Weld County gardeners in Zone 5a 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.