Blog

When to plant Mint in Phillips County County,

Plant Mint in Phillips County County, between May 25 and June 8 — the only viable window. Zone 3b's short season (126 frost-free days) rules out a fall crop.

When to Plant Mint in Phillips County, MT

Mint
Phillips County, Montana Zone 3b June

Phillips County, Montana gardeners: here's your June plan

Here's what deserves your attention in Phillips County, Montana this month. Everything below is tailored to Zone 3b and timed around your local frost dates.

Avg. last frost May 18
Avg. first frost September 21
Soil temp (4") 44°F
Watering High
Pest pressure High
Daylight 15.9 hrs
To set up a strong July, finish these tasks
  • 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.

Phillips County, Montana is in USDA Zone 3b. The average last spring frost is May 18 and the first fall frost is September 21, giving you a growing season of approximately 126 days.

At an elevation of 6,886 feet, Phillips County receives approximately 19 inches of rainfall annually with predominantly loam soil. Summer highs average 80°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.

Phillips County, MT (Zone 3b) Short season
126 days
Last Spring Frost May 18
126 growing days
First Fall Frost September 21
Share this guide:

Phillips County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.6

Drainage

Well Drained

Mint Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 19 🍅 Harvest: Jul 21 – Sep 22
Recommended (50%) ✗ May not fit
Transplant: May 25 🍅 Harvest: Jul 27 – Sep 28
Safe Start (90%) ✗ May not fit
Transplant: Jun 7 🍅 Harvest: Aug 9 – Oct 11

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 Phillips County

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

Soil pH

Your soil pH (6.7–7.6) is more alkaline than Mint prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Phillips 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

Succession Planting Mint

2
successive plantings in your 126-day season

Sow every 6.9 weeks. Last sowing by Jun 23 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 90 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 1.4" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.6" 0" ❄️ Dormant
Apr 1.9" 0" ❄️ Dormant
May 3" 2.4" 0.6" 💧 Light watering
Jun 3" 1.4" 1.6" 🚿 Regular watering
Jul 3" 1.6" 1.4" 💧 Light watering
Aug 3" 2" 1" 💧 Light watering
Sep 3" 1.4" 1.6" 🚿 Regular watering
Oct 1.8" 0" ❄️ Dormant
Nov 1.3" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Phillips 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 ~750 GDD — county provides 1,260 GDD Excellent fit

Mint Planting Timeline — Phillips County, MT

Mint Planting Calendar

Activity When Date Range
Transplant Outdoors May 25 May 25 – Jun 8
Harvest July 27 Jul 27 – Sep 28

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

Month-by-Month Timeline

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

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 3b

📆 Growing Season

126 days in Phillips County

Growing Tips for Mint in Phillips County

Direct sow Mint outdoors after May 18 in Phillips 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 Phillips County, MT?

Phillips County is in Zone 3b with an average last frost of May 18. Plan your Mint planting based on this frost date — see the calendar above for exact timing.

What planting zone is Phillips County, MT?

Phillips County, Montana is in USDA Hardiness Zone 3b. The average last spring frost is May 18 and first fall frost is September 21.

When should I plant Mint in Phillips County, ?

In Phillips County, , plant Mint after the last frost (around May 18) and before the first frost (around September 21). Best results when soil holds above 50°F.

What growing zone is Phillips County, for Mint?

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

Can Mint grow in Phillips County's climate?

Yes — Mint grows well in Phillips County's temperate climate. Phillips County averages a 126-day frost-free season, with last frost around May 18 and first frost around September 21.

🌱

Your Phillips County Garden Planner — Free

A 22-page printable planner built for Phillips County (Zone 3b). 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 Phillips County, MT. 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.