When to Plant Mint in Pierce County, WA
Mint is a vigorous perennial herb with refreshing, aromatic leaves used in teas, cocktails, and cooking. It spreads aggressively by underground runners.
Pierce County, Washington is in USDA Zone 8a. The average last spring frost is April 13 and the first fall frost is October 30, giving you a growing season of approximately 200 days.
At an elevation of 168 feet, Pierce County receives approximately 48.9 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.
Pierce County Soil Profile
Soil Type
Silt Loam
Soil pH
5.4-6.2
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.
Soil Compatibility in Pierce County
How your county's soil matches Mint's growing requirements.
Soil pH
Your soil pH (5.4–6.2) is more acidic than Mint prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Pierce County is excellent for Mint — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.4%) — Mint will thrive.
How to Plant Mint
Succession Planting Mint
Sow every 6.9 weeks. Last sowing by Aug 01 to harvest before frost.
Plant 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 | — | 6.8" | 0" | ❄️ Dormant |
| Feb | — | 5.7" | 0" | ❄️ Dormant |
| Mar | — | 4.4" | 0" | ❄️ Dormant |
| Apr | 3" | 4.1" | 0" | ✅ Rainfall sufficient |
| May | 3" | 2.8" | 0.2" | 💧 Light watering |
| Jun | 3" | 2" | 1" | 💧 Light watering |
| Jul | 3" | 0.9" | 2.1" | 🚿 Regular watering |
| Aug | 3" | 0.9" | 2.1" | 🚿 Regular watering |
| Sep | 3" | 2" | 1" | 💧 Light watering |
| Oct | 3" | 4.7" | 0" | ✅ Rainfall sufficient |
| Nov | — | 7.8" | 0" | ❄️ Dormant |
| Dec | — | 6.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Pierce 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 — Pierce County, WA
Mint Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | April 20 | Apr 20 – May 4 |
| Harvest | June 22 | Jun 22 – Aug 31 |
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 | — |
| 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: too_acidic
🗺️ USDA Zone
Zone 8a
📆 Growing Season
200 days in Pierce County
Growing Tips for Mint in Pierce County
Direct sow Mint outdoors after April 13 in Pierce 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 Pierce County, WA?
Pierce County is in Zone 8a with an average last frost of April 13. Plan your Mint planting based on this frost date — see the calendar above for exact timing.
What planting zone is Pierce County, WA?
Pierce County, Washington is in USDA Hardiness Zone 8a. The average last spring frost is April 13 and first fall frost is October 30.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Pierce County gardeners in Zone 8a organize planting dates, track what's growing, and never miss a planting window.
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