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When to Plant Broccoli in Ouray County, CO

Broccoli is a nutrient-dense cool-season crop that produces large central heads followed by smaller side shoots. It is one of the most popular garden vegetables.

Ouray County, Colorado is in USDA Zone 5a. The average last spring frost is June 18 and the first fall frost is September 10, giving you a growing season of approximately 84 days.

At an elevation of 7,449 feet, Ouray County receives approximately 12.6 inches of rainfall annually with predominantly loam soil. Summer highs average 86ยฐF, providing good warmth for Broccoli during the growing season. With low rainfall, drip irrigation is essential for growing Broccoli successfully. Mulch heavily to conserve soil moisture.

Ouray County, CO (Zone 5a) Very short season
84 days
Last Spring Frost June 18
84 growing days
First Fall Frost September 10

Ouray County Soil Profile

Soil Type

Loam

Soil pH

6.4-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (8 days to spare)
Start indoors: Apr 8 Transplant: May 13 🍅 Harvest: Jul 15 – Aug 26
Recommended (50%) ✗ May not fit
Start indoors: May 14 Transplant: Jun 18 🍅 Harvest: Aug 20 – Oct 1
Safe Start (90%) ✓ Fits season (1 days to spare)
Start indoors: May 25 Transplant: Jun 29 🍅 Harvest: Aug 31 – Oct 12

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
0.6″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 332 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” consider drought-tolerant varieties and mulching

Broccoli needs ~1,088 GDD — county provides 1,218 GDD Good fit

Broccoli Planting Timeline โ€” Ouray County, CO

Broccoli Planting Calendar

Activity When Date Range
Start Indoors May 14 May 14 โ€“ May 28
Transplant Outdoors June 18 Jun 18 โ€“ Jul 2
Direct Sow June 4 Jun 4 โ€“ Jun 25
Fall Sowing July 2 Jul 2 โ€“ Jul 16
Harvest August 20 Aug 20 โ€“ Oct 1

Plant 1" deep ยท 15" apart ยท Rows 24" 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 Fall Sowing
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

60โ€“90 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 5a

Growing Season

84 days

Growing Tips for Ouray County

Start seeds indoors 6-8 weeks before last frost. Provide consistent moisture to prevent hollow stems. Harvest heads before yellow flowers appear.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Strawberries

Level Up Your Garden

๐ŸŒพ Save Your Own Broccoli Seeds
Life Cycle Biennial
Pollination Cross-Pollinated (insects)
How to Collect Allow plants to flower 2nd year; collect dry pods.
Storage Store airtight; viable 5 years at 35ยฐF, under 50% humidity.

Isolate 1/2 mile from other brassicas. Biennial โ€” must overwinter roots.

Frequently Asked Questions

When should I plant Broccoli in Ouray County, CO?

Ouray County is in Zone 5a with an average last frost of June 18. Plan your Broccoli planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Ouray County, CO?

Ouray County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is June 18 and first fall frost is September 10.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Ouray 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.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Ouray County, CO. Local conditions may vary. Last updated: April 2026.