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When to Plant Mint in Willamina, OR

Mint
Willamina, OR Zone 8b June

June to-do list for Willamina, OR

Your Willamina, OR garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost April 15
Avg. first frost October 27
Soil temp (4") 80°F
Watering High
Pest pressure High
Daylight 15.4 hrs
  1. Harvest mint as they ripen

    If you can't use it all right away, check the food-preservation section of your planner.

Looking ahead to July
  • 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.

Willamina, Oregon is in USDA Zone 8b. The average last spring frost is April 15 and the first fall frost is October 27, giving you a growing season of approximately 195 days.

At an elevation of 476 feet, Yamhill County receives approximately 54.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Mint during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Mint root diseases.

Willamina, OR (Zone 8b) Moderate season
195 days
Last Spring Frost April 15
195 growing days
First Fall Frost October 27
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Willamina Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.2

Drainage

Well Drained

Mint Planting Risk Windows

Early Start (70% safe) ✓ Fits season (53 days to spare)
Transplant: Apr 15 🍅 Harvest: Jun 17 – Aug 26
Recommended (50%) ✓ Fits season (55 days to spare)
Transplant: Apr 22 🍅 Harvest: Jun 24 – Sep 2
Safe Start (90%) ✓ Fits season (56 days to spare)
Transplant: May 15 🍅 Harvest: Jul 17 – Sep 25

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 Willamina

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 Yamhill 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 195-day season

Sow every 6.9 weeks. Last sowing by Jul 29 to harvest before frost.

Mint Water Budget

Plant needs
0.7″/week
Rainfall provides
1.2″/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 7.4" 0" ❄️ Dormant
Feb 6.4" 0" ❄️ Dormant
Mar 5.1" 0" ❄️ Dormant
Apr 3" 3.5" 0" ✅ Rainfall sufficient
May 3" 2.8" 0.2" 💧 Light watering
Jun 3" 2.1" 0.9" 💧 Light watering
Jul 3" 0.9" 2.1" 🚿 Regular watering
Aug 3" 1" 2" 🚿 Regular watering
Sep 3" 2.4" 0.6" 💧 Light watering
Oct 3" 4.8" 0" ✅ Rainfall sufficient
Nov 9.3" 0" ❄️ Dormant
Dec 8.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Yamhill 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 ~1,312 GDD — county provides 3,412 GDD Excellent fit

Mint Planting Timeline — Willamina, OR

Mint Planting Calendar

Activity When Date Range
Transplant Outdoors April 22 Apr 22 – May 6
Harvest June 24 Jun 24 – Sep 2

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
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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 8b

📆 Growing Season

195 days in Yamhill County

Growing Tips for Mint in Willamina

Direct sow Mint outdoors after April 15 in Yamhill 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 →

🌱

Your Yamhill County Garden Planner — Free

A 22-page printable planner built for Yamhill County (Zone 8b). 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 Yamhill County, OR. Local conditions may vary. Last updated: June 2026.