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When to Plant Mint in Adams County, ID

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

Adams County, Idaho is in USDA Zone 5a. The average last spring frost is May 20 and the first fall frost is September 25, giving you a growing season of approximately 128 days.

At an elevation of 6,593 feet, Adams County receives approximately 20.6 inches of rainfall annually with predominantly loam soil. Summer highs average 85ยฐF, providing good warmth for Mint during the growing season.

Adams County, ID (Zone 5a) Short season
128 days
Last Spring Frost May 20
128 growing days
First Fall Frost September 25

Adams County Soil Profile

Soil Type

Loam

Soil pH

6.3-8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 12 🍅 Harvest: Jul 14 – Sep 22
Recommended (50%) ✗ May not fit
Transplant: May 27 🍅 Harvest: Jul 29 – Oct 7
Safe Start (90%) ✗ May not fit
Transplant: Jun 30 🍅 Harvest: Sep 1 – Nov 10

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
0.7″/week
You supply
1.5″/week
Watering frequency 2-3 times/week
Season total 1,742 gal / 100 sq ft
Drought risk

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

Mint needs ~1,031 GDD — county provides 1,760 GDD Excellent fit

Mint Planting Timeline โ€” Adams County, ID

Mint Planting Calendar

Activity When Date Range
Transplant Outdoors May 27 May 27 โ€“ Jun 10
Harvest July 29 Jul 29 โ€“ Oct 7

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 Transplant Outdoors
June Transplant Outdoors
July Harvest
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

128 days

Growing Tips for Adams 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 Adams County, ID?

Adams County is in Zone 5a with an average last frost of May 20. Plan your Mint planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Adams County, ID?

Adams County, Idaho is in USDA Hardiness Zone 5a. The average last spring frost is May 20 and first fall frost is September 25.

๐ŸŒฑ

Plan Your Garden with Confidence

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