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When to Plant Squash (Summer) in Montrose County, CO

Summer squash includes zucchini, yellow crookneck, and pattypan varieties that are harvested young and tender. They are prolific producers in warm weather.

Montrose County, Colorado is in USDA Zone 6a. The average last spring frost is June 13 and the first fall frost is September 12, giving you a growing season of approximately 91 days.

At an elevation of 6,494 feet, Montrose County receives approximately 18.4 inches of rainfall annually with predominantly loam soil. Summer highs average 87ยฐF, providing good warmth for Squash (Summer) during the growing season. With low rainfall, drip irrigation is essential for growing Squash (Summer) successfully. Mulch heavily to conserve soil moisture.

Montrose County, CO (Zone 6a) Very short season
91 days
Last Spring Frost June 13
91 growing days
First Fall Frost September 12

Montrose County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 9 Transplant: May 28 🍅 Harvest: Jul 16 – Sep 17
Recommended (50%) ✗ May not fit
Start indoors: May 9 Transplant: Jun 27 🍅 Harvest: Aug 15 – Oct 17
Safe Start (90%) ✗ May not fit
Start indoors: May 22 Transplant: Jul 10 🍅 Harvest: Aug 28 – Oct 30

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
0.9″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 147 gal / 100 sq ft
Drought risk

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

Squash (Summer) needs ~839 GDD — county provides 1,387 GDD Excellent fit

Squash (Summer) Planting Timeline โ€” Montrose County, CO

Squash (Summer) Planting Calendar

Activity When Date Range
Start Indoors May 9 May 9 โ€“ May 23
Transplant Outdoors June 27 Jun 27 โ€“ Jul 11
Direct Sow June 20 Jun 20 โ€“ Jul 11
Harvest August 15 Aug 15 โ€“ Oct 17

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

45โ€“65 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 6a

Growing Season

91 days

Growing Tips for Montrose County

Direct sow after last frost on mounds. Harvest frequently when fruits are 6-8 inches for best texture. Check plants daily as they grow rapidly in summer heat.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Level Up Your Garden

Frequently Asked Questions

When should I plant Squash (Summer) in Montrose County, CO?

Montrose County is in Zone 6a with an average last frost of June 13. Plan your Squash (Summer) planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Montrose County, CO?

Montrose County, Colorado is in USDA Hardiness Zone 6a. The average last spring frost is June 13 and first fall frost is September 12.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Montrose 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 Montrose County, CO. Local conditions may vary. Last updated: April 2026.