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When to Plant Mint in Rio Blanco County, CO

Mint is a vigorous perennial herb with refreshing, aromatic leaves used in teas, cocktails, and cooking. It spreads aggressively by underground runners.

Rio Blanco County, Colorado is in USDA Zone 5a. The average last spring frost is June 2 and the first fall frost is September 17, giving you a growing season of approximately 107 days.

At an elevation of 6,974 feet, Rio Blanco County receives approximately 19 inches of rainfall annually with predominantly loam soil. Summer highs average 86ยฐF, providing good warmth for Mint during the growing season. With low rainfall, drip irrigation is essential for growing Mint successfully. Mulch heavily to conserve soil moisture.

Rio Blanco County, CO (Zone 5a) Short season
107 days
Last Spring Frost June 2
107 growing days
First Fall Frost September 17

Rio Blanco County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 26 🍅 Harvest: Jul 28 – Oct 6
Recommended (50%) ✗ May not fit
Transplant: Jun 9 🍅 Harvest: Aug 11 – Oct 20
Safe Start (90%) ✗ May not fit
Transplant: Jun 27 🍅 Harvest: Aug 29 – Nov 7

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
1.5″/week
Rainfall provides
0.8″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 862 gal / 100 sq ft
Drought risk

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

Mint needs ~1,088 GDD — county provides 1,551 GDD Excellent fit

Mint Planting Timeline โ€” Rio Blanco County, CO

Mint Planting Calendar

Activity When Date Range
Transplant Outdoors June 9 Jun 9 โ€“ Jun 23
Harvest August 11 Aug 11 โ€“ Oct 20

Plant 0.5" deep ยท 8" apart ยท Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

High โ€” keep soil consistently moist

Days to Maturity

60โ€“90 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 5a

Growing Season

107 days

Growing Tips for Rio Blanco County

Always grow mint in containers or with underground barriers to control spreading. Harvest regularly to keep plants compact. Cut plants back in late summer for a fresh fall flush.

Companion Planting

Good Companions

Avoid Planting Near

  • Parsley

Level Up Your Garden

Frequently Asked Questions

When should I plant Mint in Rio Blanco County, CO?

Rio Blanco County is in Zone 5a with an average last frost of June 2. Plan your Mint planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Rio Blanco County, CO?

Rio Blanco County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is June 2 and first fall frost is September 17.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Rio Blanco County gardeners in Zone 5a 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 Rio Blanco County, CO. Local conditions may vary. Last updated: April 2026.