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When to Plant Mint in Gunnison County, CO

Gunnison County, Colorado Zone 5a May

Your May gardening checklist

Your garden in Gunnison County, Colorado is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost June 12
Avg. first frost September 10
Soil temp (4") 34°F
Watering High
Pest pressure Low
Daylight 14.1 hrs
Before June arrives, get these ready
  • Transplants going out: mint

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

Gunnison County, Colorado is in USDA Zone 5a. The average last spring frost is June 12 and the first fall frost is September 10, giving you a growing season of approximately 90 days.

At an elevation of 7,435 feet, Gunnison County receives approximately 17.9 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Mint to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Mint successfully. Mulch heavily to conserve soil moisture.

Gunnison County, CO (Zone 5a) Very short season
90 days
Last Spring Frost June 12
90 growing days
First Fall Frost September 10
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Gunnison County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Jun 5 🍅 Harvest: Aug 7 – Oct 16
Recommended (50%) ✗ May not fit
Transplant: Jun 19 🍅 Harvest: Aug 21 – Oct 30
Safe Start (90%) ✗ May not fit
Transplant: Jul 2 🍅 Harvest: Sep 3 – Nov 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.

Soil Compatibility in Gunnison County

How your county's soil matches Mint's growing requirements.

Soil pH

Your soil pH (6.5–7.9) is more alkaline than Mint prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Gunnison County is excellent for Mint — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Mint.

How to Plant Mint

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Mint

Mint needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Mint Needs Rainfall You Supplement Action
Jan 1.2" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 2" 0" ❄️ Dormant
May 2.2" 0" ❄️ Dormant
Jun 3" 1.3" 1.7" 🚿 Regular watering
Jul 3" 1.7" 1.3" 💧 Light watering
Aug 3" 1.6" 1.4" 💧 Light watering
Sep 3" 1.5" 1.5" 🚿 Regular watering
Oct 1.4" 0" ❄️ Dormant
Nov 1.2" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Gunnison County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Mint 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.

Mint needs ~919 GDD — county provides 1,102 GDD Good fit

Mint Planting Timeline — Gunnison County, CO

Mint Planting Calendar

Activity When Date Range
Transplant Outdoors June 19 Jun 19 – Jul 3
Harvest August 21 Aug 21 – Oct 30

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May
June Transplant Outdoors
July Transplant Outdoors
August Harvest
September Harvest
October Harvest
November
December
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Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.7"/week · Natural rainfall sufficient

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5a

📆 Growing Season

90 days in Gunnison County

Growing Tips for Mint in Gunnison County

Direct sow Mint outdoors after June 12 in Gunnison County when soil has warmed and frost danger has passed.

Your 90.0-day growing season in Gunnison County is tight for Mint (60.0-90.0 days to maturity). Start indoors and choose early-maturing varieties.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Mint in Gunnison County, CO?

Gunnison County is in Zone 5a with an average last frost of June 12. Plan your Mint planting based on this frost date — see the calendar above for exact timing.

What planting zone is Gunnison County, CO?

Gunnison County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is June 12 and first fall frost is September 10.

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Your Gunnison County Garden Planner — Free

A 24-page printable planner built for Gunnison County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Gunnison County, CO. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.