Blog

When to Plant Mint in Shelby County, MO

Shelby County, Missouri Zone 6a May

This month in Shelby County, Missouri

A quick May briefing for Shelby County, Missouri gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 17
Avg. first frost October 17
Soil temp (4") 59°F
Watering Low
Pest pressure Low
Daylight 14.2 hrs
Coming up in June — start thinking about
  • 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.

Shelby County, Missouri is in USDA Zone 6a. The average last spring frost is April 17 and the first fall frost is October 17, giving you a growing season of approximately 183 days.

At an elevation of 1,216 feet, Shelby County receives approximately 40.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Mint to ensure they mature before fall.

Shelby County, MO (Zone 6a) Moderate season
183 days
Last Spring Frost April 17
183 growing days
First Fall Frost October 17

Shelby County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (42 days to spare)
Transplant: Apr 19 🍅 Harvest: Jun 21 – Aug 30
Recommended (50%) ✓ Fits season (43 days to spare)
Transplant: Apr 24 🍅 Harvest: Jun 26 – Sep 4
Safe Start (90%) ✓ Fits season (44 days to spare)
Transplant: May 7 🍅 Harvest: Jul 9 – Sep 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 Shelby County

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

Soil pH

Your soil pH (5.7–6.8) overlaps with Mint's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.0%). Annual compost additions will help Mint.

How to Plant Mint

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

Succession Planting Mint

3
successive plantings in your 183-day season

Sow every 6.9 weeks. Last sowing by Jul 19 to harvest before frost.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

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 1.8" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 3" 4" 0" ✅ Rainfall sufficient
May 3" 5.1" 0" ✅ Rainfall sufficient
Jun 3" 4.9" 0" ✅ Rainfall sufficient
Jul 3" 4.8" 0" ✅ Rainfall sufficient
Aug 3" 4.2" 0" ✅ Rainfall sufficient
Sep 3" 3.4" 0" ✅ Rainfall sufficient
Oct 3" 3.2" 0" ✅ Rainfall sufficient
Nov 2.6" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Shelby 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 2,379 GDD Excellent fit

Mint Planting Timeline — Shelby County, MO

Mint Planting Calendar

Activity When Date Range
Transplant Outdoors April 24 Apr 24 – May 8
Harvest June 26 Jun 26 – Sep 4

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.7"/week · Natural rainfall sufficient

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 6a

📆 Growing Season

183 days in Shelby County

Growing Tips for Mint in Shelby County

Direct sow Mint outdoors after April 17 in Shelby 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 Shelby County, MO?

Shelby County is in Zone 6a with an average last frost of April 17. Plan your Mint planting based on this frost date — see the calendar above for exact timing.

What planting zone is Shelby County, MO?

Shelby County, Missouri is in USDA Hardiness Zone 6a. The average last spring frost is April 17 and first fall frost is October 17.

🌱

Your Shelby County Garden Planner — Free

A 24-page printable planner built for Shelby County (Zone 6a). 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 Shelby County, MO. 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.