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When to plant Mint in Hardin County, IA

Plant Mint in Hardin County during the brief May 5–May 19 window. With 164 frost-free days, fall plantings can't mature before October 9.

When to Plant Mint in Hardin County, IA

Mint

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

Hardin County, Iowa is in USDA Zone 5a. The average last spring frost is April 28 and the first fall frost is October 9, giving you a growing season of approximately 164 days.

At an elevation of 507 feet, Hardin County receives approximately 40.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Mint to ensure they mature before fall.

Hardin County, IA (Zone 5a) Moderate season
164 days
Last Spring Frost April 28
164 growing days
First Fall Frost October 9

Hardin County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.9

Drainage

Well Drained

Monthly Watering Guide for Mint

Mint needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Mint Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 3.1" 0" ❄️ Dormant
Apr 4.3" 4.1" 0.2" 💧 Light watering
May 4.3" 4.1" 0.2" 💧 Light watering
Jun 4.3" 4.4" 0" ✅ Rainfall sufficient
Jul 4.3" 5.1" 0" ✅ Rainfall sufficient
Aug 4.3" 3.9" 0.4" 💧 Light watering
Sep 4.3" 3.7" 0.6" 💧 Light watering
Oct 4.3" 3.4" 0.9" 💧 Light watering
Nov 2.9" 0" ❄️ Dormant
Dec 2.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Hardin County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Mint Planting Timeline — Hardin County, IA

Mint Planting Calendar

Activity When Date Range
Transplant Outdoors May 5 May 5 – May 19
Harvest July 7 Jul 7 – Sep 15

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

High — keep soil consistently moist

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 5a

📆 Growing Season

164 days in Hardin County

Growing Tips for Hardin County

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 Hardin County, IA?

Hardin County is in Zone 5a with an average last frost of April 28. Plan your Mint planting based on this frost date — see the calendar above for exact timing.

What planting zone is Hardin County, IA?

Hardin County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 28 and first fall frost is October 9.

When should I plant Mint in Hardin County, IA?

In Hardin County, IA, plant Mint after the last frost (around April 28) and before the first frost (around October 9). Best results when soil holds above 50°F.

What growing zone is Hardin County, IA for Mint?

Hardin 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 Hardin County's climate?

Yes — Mint grows well in Hardin County's temperate climate. Hardin County averages a 164-day frost-free season, with last frost around April 28 and first frost around October 9.

🌱

Your Hardin County Garden Planner — Free

A 22-page printable planner built for Hardin 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.

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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 Hardin County, IA. Local conditions may vary. Last updated: July 2026.

Sources & credits

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