When to Plant Hubbard Squash in Washington County, CO
Hubbard squash is a large, bumpy-skinned winter squash with dense, sweet, dry flesh ideal for baking and pies. The hard shell allows storage for 6 months or more.
Washington County, Colorado is in USDA Zone 5a. The average last spring frost is May 10 and the first fall frost is October 5, giving you a growing season of approximately 148 days.
At an elevation of 6,091 feet, Washington County receives approximately 13 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Hubbard Squash during the growing season. With low rainfall, drip irrigation is essential for growing Hubbard Squash successfully. Mulch heavily to conserve soil moisture.
Washington County Soil Profile
Soil Type
Loam
Soil pH
6.8-8.3
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.
Plant Water Budget
Water stress score is 10/10 — consider drought-tolerant varieties and mulching
Hubbard Squash Planting Timeline — Washington County, CO
Hubbard Squash Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 5 | Apr 5 – Apr 19 |
| Transplant Outdoors | May 24 | May 24 – Jun 7 |
| Direct Sow | May 17 | May 17 – Jun 7 |
| Harvest | September 6 | Sep 6 – Oct 11 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | Transplant Outdoors Direct Sow |
| July | — |
| August | — |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
Sun
Full Sun (6-8+ hours)
Water
Moderate — regular watering
Days to Maturity
100–120 days
Soil pH
6 – 7
USDA Zone
Zone 5a
Growing Season
148 days
Growing Tips for Washington County
Start seeds indoors in short-season areas. Requires ample space and rich soil. Harvest when the skin is very hard and the color is deep. Cure in the sun before storing.
Companion Planting
Good Companions
Avoid Planting Near
Level Up Your Garden
Hubbard Squash in Other Locations
Frequently Asked Questions
When should I plant Hubbard Squash in Washington County, CO?
Washington County is in Zone 5a with an average last frost of May 10. Plan your Hubbard Squash planting based on this frost date — see the calendar above for exact timing.
What planting zone is Washington County, CO?
Washington County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is May 10 and first fall frost is October 5.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Washington County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.
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