When to Plant Mint in Boundary County, ID
Mint is a vigorous perennial herb with refreshing, aromatic leaves used in teas, cocktails, and cooking. It spreads aggressively by underground runners.
Boundary County, Idaho is in USDA Zone 5b. The average last spring frost is May 10 and the first fall frost is September 22, giving you a growing season of approximately 135 days.
At an elevation of 5,105 feet, Boundary County receives approximately 21.1 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Mint during the growing season.
Boundary County Soil Profile
Soil Type
Loam
Soil pH
6.7-8.3
Drainage
Well Drained
Plant 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.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Mint Planting Timeline — Boundary County, ID
Mint Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 17 | May 17 – May 31 |
| Harvest | July 19 | Jul 19 – Sep 27 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| 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
6 – 7
USDA Zone
Zone 5b
Growing Season
135 days
Growing Tips for Boundary 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
Level Up Your Garden
Mint in Other Locations
Frequently Asked Questions
When should I plant Mint in Boundary County, ID?
Boundary County is in Zone 5b with an average last frost of May 10. Plan your Mint planting based on this frost date — see the calendar above for exact timing.
What planting zone is Boundary County, ID?
Boundary County, Idaho is in USDA Hardiness Zone 5b. The average last spring frost is May 10 and first fall frost is September 22.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Boundary County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.
Get Your Free Garden Planner →Free download. Plan your entire garden season in minutes.