Blog

When to plant Mint in Caribou County, ID

In Caribou County, Mint is a single-season spring crop — there's no second fall window. Plant June 6–June 20 for an 60–90-day harvest, finishing well before the September 16 first frost.

When to Plant Mint in Caribou County, ID

Mint
Caribou County, Idaho Zone 5a July

Your July gardening checklist

Each item below is timed to Caribou County, Idaho's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost May 30
Avg. first frost September 16
Soil temp (4") 55°F
Watering High
Pest pressure High
Daylight 14.9 hrs
Looking ahead to August
  • First harvests: mint

Instant PDF download. No spam, unsubscribe any time.

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

Caribou County, Idaho is in USDA Zone 5a. The average last spring frost is May 30 and the first fall frost is September 16, giving you a growing season of approximately 109 days.

At an elevation of 6,562 feet, Caribou County receives approximately 15.3 inches of rainfall annually with predominantly loam soil. Summer highs average 81°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.

Caribou County, ID (Zone 5a) Short season
109 days
Last Spring Frost May 30
109 growing days
First Fall Frost September 16

Caribou County Soil Profile

Soil Type

Loam

Soil pH

6.8-8.1

Drainage

Well Drained

Mint Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 25 🍅 Harvest: Jul 27 – Oct 5
Recommended (50%) ✗ May not fit
Transplant: Jun 6 🍅 Harvest: Aug 8 – Oct 17
Safe Start (90%) ✗ May not fit
Transplant: Jun 24 🍅 Harvest: Aug 26 – Nov 4

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 Caribou County

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

Soil pH

Your soil pH (6.8–8.1) is more alkaline than Mint prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Mint.

How to Plant Mint

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

Succession Planting Mint

2
successive plantings in your 109-day season

Sow every 6.9 weeks. Last sowing by Jun 18 to harvest before frost.

Mint Water Budget

Plant needs
0.7″/week
Rainfall provides
0.6″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 129 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 0.9" 0" ❄️ Dormant
Mar 1.4" 0" ❄️ Dormant
Apr 1.7" 0" ❄️ Dormant
May 3" 1.6" 1.4" 💧 Light watering
Jun 3" 1" 2" 🚿 Regular watering
Jul 3" 1.5" 1.5" 🚿 Regular watering
Aug 3" 1.4" 1.6" 🚿 Regular watering
Sep 3" 1.2" 1.8" 🚿 Regular watering
Oct 1.4" 0" ❄️ Dormant
Nov 1.1" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Caribou 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 ~806 GDD — county provides 1,171 GDD Excellent fit

Mint Planting Timeline — Caribou County, ID

Mint Planting Calendar

Activity When Date Range
Transplant Outdoors June 6 Jun 6 – Jun 20
Harvest August 8 Aug 8 – Oct 17

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 5a

📆 Growing Season

109 days in Caribou County

Growing Tips for Mint in Caribou County

Direct sow Mint outdoors after May 30 in Caribou County when soil has warmed and frost danger has passed.

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 Caribou County, ID?

Caribou County is in Zone 5a with an average last frost of May 30. Plan your Mint planting based on this frost date — see the calendar above for exact timing.

What planting zone is Caribou County, ID?

Caribou County, Idaho is in USDA Hardiness Zone 5a. The average last spring frost is May 30 and first fall frost is September 16.

When should I plant Mint in Caribou County, ID?

In Caribou County, ID, plant Mint after the last frost (around May 30) and before the first frost (around September 16). Best results when soil holds above 50°F.

What growing zone is Caribou County, ID for Mint?

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

Can Mint grow in Caribou County's climate?

Yes — Mint grows well in Caribou County's temperate climate. Caribou County averages a 109-day frost-free season, with last frost around May 30 and first frost around September 16.

🌱

Your Caribou County Garden Planner — Free

A 22-page printable planner built for Caribou 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.

Instant PDF download. No spam, unsubscribe any time.

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

Sources & credits

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