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When to plant Mint in Mark, IL

In Mark, Mint is a single-season spring crop — there's no second fall window. Plant April 28–May 12 for an 60–90-day harvest, finishing well before the October 13 first frost.

When to Plant Mint in Mark, IL

Mint
Putnam County, Illinois Zone 5b July

Your July gardening checklist

July is a pivotal month for Putnam County, Illinois gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 21
Avg. first frost October 13
Soil temp (4") 78°F
Watering Low
Pest pressure High
Daylight 14.7 hrs
  1. Pick mint

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

To set up a strong August, finish these tasks
  • First harvests: mint

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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.

Mark, Illinois is in USDA Zone 5b. The average last spring frost is April 21 and the first fall frost is October 13, giving you a growing season of approximately 175 days.

At an elevation of 582 feet, Putnam County receives approximately 41.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Mint during the growing season.

Mark, IL (Zone 5b) Moderate season
175 days
Last Spring Frost April 21
175 growing days
First Fall Frost October 13

Mark Soil Profile

Soil Type

Silt Loam

Soil pH

6-6.7

Drainage

Well Drained

Mint Planting Risk Windows

Early Start (70% safe) ✓ Fits season (35 days to spare)
Transplant: Apr 23 🍅 Harvest: Jun 25 – Sep 3
Recommended (50%) ✓ Fits season (35 days to spare)
Transplant: Apr 28 🍅 Harvest: Jun 30 – Sep 8
Safe Start (90%) ✓ Fits season (32 days to spare)
Transplant: May 16 🍅 Harvest: Jul 18 – Sep 26

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 Mark

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

Soil pH

Your soil pH (6.0–6.7) is within Mint's preferred range (6.0–7.0).

Soil Texture

The silt loam soil in Putnam 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 (4.3%) — Mint will thrive.

How to Plant Mint

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

Succession Planting Mint

3
successive plantings in your 175-day season

Sow every 6.9 weeks. Last sowing by Jul 15 to harvest before frost.

Mint Water Budget

Plant needs
0.7″/week
Rainfall provides
1.0″/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 2" 0" ❄️ Dormant
Mar 3.1" 0" ❄️ Dormant
Apr 3" 3.6" 0" ✅ Rainfall sufficient
May 3" 4.3" 0" ✅ Rainfall sufficient
Jun 3" 5.2" 0" ✅ Rainfall sufficient
Jul 3" 5" 0" ✅ Rainfall sufficient
Aug 3" 4.3" 0" ✅ Rainfall sufficient
Sep 3" 3.3" 0" ✅ Rainfall sufficient
Oct 3" 3.3" 0" ✅ Rainfall sufficient
Nov 3.2" 0" ❄️ Dormant
Dec 2.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Putnam 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 ~1,144 GDD — county provides 2,668 GDD Excellent fit

Mint Planting Timeline — Mark, IL

Mint Planting Calendar

Activity When Date Range
Transplant Outdoors April 28 Apr 28 – May 12
Harvest June 30 Jun 30 – Sep 8

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: ideal

🗺️ USDA Zone

Zone 5b

📆 Growing Season

175 days in Putnam County

Growing Tips for Mint in Mark

Direct sow Mint outdoors after April 21 in Putnam 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 →

When should I plant Mint in Mark, IL?

In Mark, IL, plant Mint after the last frost (around April 21) and before the first frost (around October 13). Best results when soil holds above 50°F.

What growing zone is Mark, IL for Mint?

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

Can Mint grow in Mark's climate?

Yes — Mint grows well in Mark's temperate climate. Mark averages a 175-day frost-free season, with last frost around April 21 and first frost around October 13.

🌱

Your Putnam County Garden Planner — Free

A 22-page printable planner built for Putnam County (Zone 5b). 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 Putnam County, IL. Local conditions may vary. Last updated: July 2026.