When to plant Mint in St. Louis County, MN
In St. Louis County, Mint is a single-season spring crop — there's no second fall window. Plant June 9–June 23 for an 60–90-day harvest, finishing well before the September 10 first frost.
When to Plant Mint in St. Louis County, MN
Your August game plan for St. Louis County, Minnesota
Your St. Louis County, Minnesota garden is entering a new phase. Here's what's on the schedule for August and why each task matters now.
-
Collect mint at their peak
If you can't use it all right away, check the food-preservation section of your planner.
Coming up in September — start thinking about
- 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.
St. Louis County, Minnesota is in USDA Zone 3b. The average last spring frost is June 2 and the first fall frost is September 10, giving you a growing season of approximately 100 days.
At an elevation of 531 feet, St. Louis County receives approximately 36.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 78°F, so choose short-season varieties of Mint to ensure they mature before fall.
St. Louis County Soil Profile
Soil Type
Silt Loam
Soil pH
6-7
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 St. Louis County
How your county's soil matches Mint's growing requirements.
Soil pH
Your soil pH (6.0–7.0) is within Mint's preferred range (6.0–7.0).
Soil Texture
The silt loam soil in St. Louis 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 (4.0%) — Mint will thrive.
How to Plant Mint
Mint Water Budget
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 | — | 1.6" | 0" | ❄️ Dormant |
| Feb | — | 1.7" | 0" | ❄️ Dormant |
| Mar | — | 2.7" | 0" | ❄️ Dormant |
| Apr | — | 3.2" | 0" | ❄️ Dormant |
| May | — | 3.9" | 0" | ❄️ Dormant |
| Jun | 3" | 5.1" | 0" | ✅ Rainfall sufficient |
| Jul | 3" | 4.4" | 0" | ✅ Rainfall sufficient |
| Aug | 3" | 3.7" | 0" | ✅ Rainfall sufficient |
| Sep | 3" | 3.1" | 0" | ✅ Rainfall sufficient |
| Oct | — | 2.8" | 0" | ❄️ Dormant |
| Nov | — | 2.3" | 0" | ❄️ Dormant |
| Dec | — | 1.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Jun–Sep in St. Louis 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 — St. Louis County, MN
Mint Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | June 9 | Jun 9 – Jun 23 |
| Harvest | August 11 | Aug 11 – Oct 13 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | — |
| June | Transplant Outdoors |
| July | — |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| 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 3b
📆 Growing Season
100 days in St. Louis County
Growing Tips for Mint in St. Louis County
Direct sow Mint outdoors after June 02 in St. Louis County when soil has warmed and frost danger has passed.
Your 100.0-day growing season in St. Louis County is tight for Mint (60.0-90.0 days to maturity). Start indoors and choose early-maturing varieties.
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 St. Louis County, MN?
St. Louis County is in Zone 3b with an average last frost of June 2. Plan your Mint planting based on this frost date — see the calendar above for exact timing.
What planting zone is St. Louis County, MN?
St. Louis County, Minnesota is in USDA Hardiness Zone 3b. The average last spring frost is June 2 and first fall frost is September 10.
When should I plant Mint in St. Louis County, MN?
In St. Louis County, MN, plant Mint after the last frost (around June 2) and before the first frost (around September 10). Best results when soil holds above 50°F.
What growing zone is St. Louis County, MN for Mint?
St. Louis County sits in USDA Zone 3b. Mint grows reliably in zones 3a through 10b, so it's a good fit here.
Can Mint grow in St. Louis County's climate?
Yes — Mint grows well in St. Louis County's temperate climate. St. Louis County averages a 100-day frost-free season, with last frost around June 2 and first frost around September 10.
Your St. Louis County Garden Planner — Free
A 22-page printable planner built for St. Louis County (Zone 3b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.