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When to Plant Garlic in Mason County, WA

Mason County, Washington Zone 8b May

Your May gardening checklist

Your garden in Mason County, Washington is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost April 18
Avg. first frost October 29
Soil temp (4") 68°F
Watering High
Pest pressure High
Daylight 14.9 hrs

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Garlic is a pungent allium planted in fall and harvested the following summer. Hardneck varieties produce edible flower stalks (scapes) and are more cold-hardy.

Mason County, Washington is in USDA Zone 8b. The average last spring frost is April 18 and the first fall frost is October 29, giving you a growing season of approximately 194 days.

At an elevation of 230 feet, Mason County receives approximately 36.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Garlic during the growing season.

Mason County, WA (Zone 8b) Moderate season
194 days
Last Spring Frost April 18
194 growing days
First Fall Frost October 29

Mason County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Apr 5 🍅 Harvest: Jul 5 – Dec 20
Recommended (50%) ✓ Fits season (300 days to spare)
Transplant: Apr 18 🍅 Harvest: Jul 18 – Jan 2
Safe Start (90%) ✓ Fits season (313 days to spare)
Transplant: May 9 🍅 Harvest: Aug 8 – Jan 23

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 Mason County

How your county's soil matches Garlic's growing requirements.

Soil pH

Your soil pH (5.4–6.7) overlaps with Garlic's range (6.0–7.5), though not a perfect match.

Soil Texture

The silt loam soil in Mason County is excellent for Garlic — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.3%) — Garlic will thrive.

How to Plant Garlic

1"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 6 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Garlic

Garlic needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Garlic Needs Rainfall You Supplement Action
Jan 5" 0" ❄️ Dormant
Feb 3.7" 0" ❄️ Dormant
Mar 4.1" 0" ❄️ Dormant
Apr 2.2" 2.9" 0" ✅ Rainfall sufficient
May 2.2" 1.8" 0.4" 💧 Light watering
Jun 2.2" 1.5" 0.7" 💧 Light watering
Jul 2.2" 0.6" 1.6" 🚿 Regular watering
Aug 2.2" 0.7" 1.5" 🚿 Regular watering
Sep 2.2" 1.3" 0.9" 💧 Light watering
Oct 2.2" 3.2" 0" ✅ Rainfall sufficient
Nov 6.5" 0" ❄️ Dormant
Dec 5.3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Mason County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Garlic 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.

Garlic needs ~2,269 GDD — county provides 2,667 GDD Good fit

Garlic Planting Timeline — Mason County, WA

Garlic Planting Calendar

Activity When Date Range
Fall Sowing September 17 Sep 17 – Oct 1

Plant 1" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May
June
July
August
September Fall Sowing
October Fall Sowing
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

90–240 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 8b

📆 Growing Season

194 days in Mason County

Growing Tips for Garlic in Mason County

Direct sow Garlic outdoors after April 18 in Mason County when soil has warmed and frost danger has passed.

Your 194.0-day growing season in Mason County is tight for Garlic (90.0-240.0 days to maturity). Start indoors and choose early-maturing varieties.

Common pests for Garlic in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.

General growing tips

Plant individual cloves pointed end up in fall, 6 weeks before ground freezes. Mulch heavily with straw. Harvest when lower leaves begin to brown but 5-6 green leaves remain.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans
  • Asparagus

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Garlic in Mason County, WA?

Mason County is in Zone 8b with an average last frost of April 18. Plan your Garlic planting based on this frost date — see the calendar above for exact timing.

What planting zone is Mason County, WA?

Mason County, Washington is in USDA Hardiness Zone 8b. The average last spring frost is April 18 and first fall frost is October 29.

🌱

Your Mason County Garden Planner — Free

A 24-page printable planner built for Mason 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 Mason County, WA. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.