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When to plant Mint in Lemhi County County,

Lemhi County County sits in cold Zone 5b. Plant Mint June 16–June 30 for the single annual harvest; the September 14 first frost closes the window.

When to Plant Mint in Lemhi County, ID

Mint
Lemhi County, Idaho Zone 5b June

Your June game plan for Lemhi County, Idaho

Here's what deserves your attention in Lemhi County, Idaho this month. Everything below is tailored to Zone 5b and timed around your local frost dates.

Avg. last frost June 9
Avg. first frost September 14
Soil temp (4") 43°F
Watering Critical
Pest pressure High
Daylight 15.4 hrs
  1. Transplant mint outside

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

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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.

Lemhi County, Idaho is in USDA Zone 5b. The average last spring frost is June 9 and the first fall frost is September 14, giving you a growing season of approximately 97 days.

At an elevation of 6,743 feet, Lemhi County receives approximately 12.6 inches of rainfall annually with predominantly loam soil. Summer highs average 84°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.

Lemhi County, ID (Zone 5b) Very short season
97 days
Last Spring Frost June 9
97 growing days
First Fall Frost September 14

Lemhi County Soil Profile

Soil Type

Loam

Soil pH

6.2-8.2

Drainage

Well Drained

Mint Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 21 🍅 Harvest: Jul 23 – Oct 1
Recommended (50%) ✗ May not fit
Transplant: Jun 16 🍅 Harvest: Aug 18 – Oct 27
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 Lemhi County

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

Soil pH

Your soil pH (6.2–8.2) is more alkaline than Mint prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help Mint.

How to Plant Mint

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

Mint Water Budget

Plant needs
0.7″/week
Rainfall provides
0.6″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 160 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 0.8" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1" 0" ❄️ Dormant
Apr 1.3" 0" ❄️ Dormant
May 1.4" 0" ❄️ Dormant
Jun 3" 0.8" 2.2" 🚿 Regular watering
Jul 3" 1.3" 1.7" 🚿 Regular watering
Aug 3" 1.3" 1.7" 🚿 Regular watering
Sep 3" 1.2" 1.8" 🚿 Regular watering
Oct 1" 0" ❄️ Dormant
Nov 1" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Lemhi 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 ~975 GDD — county provides 1,261 GDD Good fit

Mint Planting Timeline — Lemhi County, ID

Mint Planting Calendar

Activity When Date Range
Transplant Outdoors June 16 Jun 16 – Jun 30
Harvest August 18 Aug 18 – Oct 27

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.7"/week · Only during dry spells

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5b

📆 Growing Season

97 days in Lemhi County

Growing Tips for Mint in Lemhi County

Direct sow Mint outdoors after June 09 in Lemhi County when soil has warmed and frost danger has passed.

Your 97.0-day growing season in Lemhi 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 Lemhi County, ID?

Lemhi County is in Zone 5b with an average last frost of June 9. Plan your Mint planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lemhi County, ID?

Lemhi County, Idaho is in USDA Hardiness Zone 5b. The average last spring frost is June 9 and first fall frost is September 14.

When should I plant Mint in Lemhi County County, ?

In Lemhi County County, , plant Mint after the last frost (around June 9) and before the first frost (around September 14). Best results when soil holds above 50°F.

What growing zone is Lemhi County County, for Mint?

Lemhi County County sits in USDA Zone 5b. Mint grows reliably in zones 3a through 10b, so it's a good fit here.

Can Mint grow in Lemhi County County's climate?

Yes — Mint grows well in Lemhi County County's temperate climate. Lemhi County County averages a 97-day frost-free season, with last frost around June 9 and first frost around September 14.

🌱

Your Lemhi County Garden Planner — Free

A 22-page printable planner built for Lemhi County (Zone 5b). 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 Lemhi County, ID. Local conditions may vary. Last updated: June 2026.

Sources & credits

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