When to plant Mint in Grundy County, IL
In Grundy County, Mint is a single-season spring crop — there's no second fall window. Plant April 27–May 11 for an 60–90-day harvest, finishing well before the October 17 first frost.
When to Plant Mint in Grundy County, IL
Grundy County, Illinois gardeners: here's your June plan
Your Grundy County, Illinois garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.
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Harvest mint as they ripen
Check every 1–2 days. Many of these get tough or go to seed if you wait too long.
Looking ahead to July
- First harvests: mint
Mint is a vigorous perennial herb with refreshing, aromatic leaves used in teas, cocktails, and cooking. It spreads aggressively by underground runners.
Grundy County, Illinois is in USDA Zone 5b. The average last spring frost is April 20 and the first fall frost is October 17, giving you a growing season of approximately 180 days.
At an elevation of 629 feet, Grundy County receives approximately 30.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Mint during the growing season.
Grundy County Soil Profile
Soil Type
Silt Loam
Soil pH
6.1-7
Drainage
Well Drained
Mint Planting Risk Windows
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 Grundy County
How your county's soil matches Mint's growing requirements.
Soil pH
Your soil pH (6.1–7.0) is within Mint's preferred range (6.0–7.0).
Soil Texture
The silt loam soil in Grundy County is excellent for Mint — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.9%). Annual compost additions will help Mint.
How to Plant Mint
Succession Planting Mint
Sow every 6.9 weeks. Last sowing by Jul 19 to harvest before frost.
Mint Water Budget
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 | — | 1.3" | 0" | ❄️ Dormant |
| Feb | — | 1.3" | 0" | ❄️ Dormant |
| Mar | — | 2" | 0" | ❄️ Dormant |
| Apr | 3" | 3.2" | 0" | ✅ Rainfall sufficient |
| May | 3" | 3.6" | 0" | ✅ Rainfall sufficient |
| Jun | 3" | 3.3" | 0" | ✅ Rainfall sufficient |
| Jul | 3" | 3.3" | 0" | ✅ Rainfall sufficient |
| Aug | 3" | 3.5" | 0" | ✅ Rainfall sufficient |
| Sep | 3" | 2.7" | 0.3" | 💧 Light watering |
| Oct | 3" | 2" | 1" | 💧 Light watering |
| Nov | — | 2.2" | 0" | ❄️ Dormant |
| Dec | — | 1.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Grundy 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 Planting Timeline — Grundy County, IL
Mint Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | April 27 | Apr 27 – May 11 |
| Harvest | June 29 | Jun 29 – Sep 7 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| 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
180 days in Grundy County
Growing Tips for Mint in Grundy County
Direct sow Mint outdoors after April 20 in Grundy 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
Check more plant combinations with our Companion Planting Checker →
Mint in Other Locations
Frequently Asked Questions
When should I plant Mint in Grundy County, IL?
Grundy County is in Zone 5b with an average last frost of April 20. Plan your Mint planting based on this frost date — see the calendar above for exact timing.
What planting zone is Grundy County, IL?
Grundy County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 20 and first fall frost is October 17.
When should I plant Mint in Grundy County, IL?
In Grundy County, IL, plant Mint after the last frost (around April 20) and before the first frost (around October 17). Best results when soil holds above 50°F.
What growing zone is Grundy County, IL for Mint?
Grundy County sits in USDA Zone 5b. Mint grows reliably in zones 3a through 10b, so it's a good fit here.
Can Mint grow in Grundy County's climate?
Yes — Mint grows well in Grundy County's temperate climate. Grundy County averages a 180-day frost-free season, with last frost around April 20 and first frost around October 17.
Your Grundy County Garden Planner — Free
A 22-page printable planner built for Grundy 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.