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When to Plant Mint in Dunn County, ND

Dunn County, North Dakota Zone 4a May

Your May game plan for Dunn County, North Dakota

Welcome to May in Zone 4a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 14
Avg. first frost September 23
Soil temp (4") 53°F
Watering High
Pest pressure Low
Daylight 14.9 hrs
  1. Harden off and plant mint

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

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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.

Dunn County, North Dakota is in USDA Zone 4a. The average last spring frost is May 14 and the first fall frost is September 23, giving you a growing season of approximately 132 days.

At an elevation of 944 feet, Dunn County receives approximately 22.3 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.

Dunn County, ND (Zone 4a) Short season
132 days
Last Spring Frost May 14
132 growing days
First Fall Frost September 23

Dunn County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 17 🍅 Harvest: Jul 19 – Sep 27
Recommended (50%) ✗ May not fit
Transplant: May 21 🍅 Harvest: Jul 23 – Oct 1
Safe Start (90%) ✗ May not fit
Transplant: Jun 6 🍅 Harvest: Aug 8 – Oct 17

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 Dunn County

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

Soil pH

Your soil pH (6.2–7.5) overlaps with Mint's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Mint is a heavy drinker but your soil drains very quickly. Mulch heavily and consider drip irrigation.

Organic Matter

Organic matter is excellent (4.2%) — Mint will thrive.

How to Plant Mint

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

Succession Planting Mint

2
successive plantings in your 132-day season

Sow every 6.9 weeks. Last sowing by Jun 25 to harvest before frost.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.7″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 283 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 1.4" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 2.2" 0" ❄️ Dormant
May 3" 2.5" 0.5" 💧 Light watering
Jun 3" 1.5" 1.5" 🚿 Regular watering
Jul 3" 1.9" 1.1" 💧 Light watering
Aug 3" 2.6" 0.4" 💧 Light watering
Sep 3" 1.9" 1.1" 💧 Light watering
Oct 2.1" 0" ❄️ Dormant
Nov 1.5" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Dunn 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 1,320 GDD Excellent fit

Mint Planting Timeline — Dunn County, ND

Mint Planting Calendar

Activity When Date Range
Transplant Outdoors May 21 May 21 – Jun 4
Harvest July 23 Jul 23 – Oct 1

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 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: acceptable

🗺️ USDA Zone

Zone 4a

📆 Growing Season

132 days in Dunn County

Growing Tips for Mint in Dunn County

Direct sow Mint outdoors after May 14 in Dunn 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 Dunn County, ND?

Dunn County is in Zone 4a with an average last frost of May 14. Plan your Mint planting based on this frost date — see the calendar above for exact timing.

What planting zone is Dunn County, ND?

Dunn County, North Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 14 and first fall frost is September 23.

🌱

Your Dunn County Garden Planner — Free

A 24-page printable planner built for Dunn County (Zone 4a). 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 Dunn County, ND. 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.