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When to Plant Garlic in Douglas County, WA

Douglas County, Washington Zone 7a May

What to do in May

We've pulled the most time-sensitive tasks for Douglas County, Washington this May and put them front and centre. Tackle them in order.

Avg. last frost May 8
Avg. first frost October 4
Soil temp (4") 54°F
Watering Critical
Pest pressure Low
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.

Douglas County, Washington is in USDA Zone 7a. The average last spring frost is May 8 and the first fall frost is October 4, giving you a growing season of approximately 149 days.

At an elevation of 2,920 feet, Douglas County receives approximately 15.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Garlic during the growing season. With low rainfall, drip irrigation is essential for growing Garlic successfully. Mulch heavily to conserve soil moisture.

Douglas County, WA (Zone 7a) Short season
149 days
Last Spring Frost May 8
149 growing days
First Fall Frost October 4
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Douglas County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Apr 19 🍅 Harvest: Jul 19 – Nov 29
Recommended (50%) ✗ May not fit
Transplant: May 8 🍅 Harvest: Aug 7 – Dec 18
Safe Start (90%) ✓ Fits season (287 days to spare)
Transplant: Jun 10 🍅 Harvest: Sep 9 – Jan 20

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 Douglas County

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

Soil pH

Your soil pH (5.5–6.2) is more acidic than Garlic prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.5%) — 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
0.5″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 87 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 2.2" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 1.2" 0" ❄️ Dormant
May 2.2" 0.8" 1.4" 🚿 Regular watering
Jun 2.2" 0.6" 1.6" 🚿 Regular watering
Jul 2.2" 0.2" 2" 🚿 Regular watering
Aug 2.2" 0.3" 1.9" 🚿 Regular watering
Sep 2.2" 0.7" 1.5" 🚿 Regular watering
Oct 2.2" 1.2" 1" 💧 Light watering
Nov 2.5" 0" ❄️ Dormant
Dec 2.7" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Douglas 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 ~2,888 GDD — county provides 2,607 GDD Tight fit

Garlic Planting Timeline — Douglas County, WA

Garlic Planting Calendar

Activity When Date Range
Fall Sowing August 23 Aug 23 – Sep 6

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Only during dry spells

📅 Days to Maturity

90–240 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 7a

📆 Growing Season

149 days in Douglas County

Growing Tips for Garlic in Douglas County

Direct sow Garlic outdoors after May 08 in Douglas County when soil has warmed and frost danger has passed.

Your 149.0-day growing season in Douglas 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 Douglas County, WA?

Douglas County is in Zone 7a with an average last frost of May 8. Plan your Garlic planting based on this frost date — see the calendar above for exact timing.

What planting zone is Douglas County, WA?

Douglas County, Washington is in USDA Hardiness Zone 7a. The average last spring frost is May 8 and first fall frost is October 4.

🌱

Your Douglas County Garden Planner — Free

A 24-page printable planner built for Douglas County (Zone 7a). 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 Douglas 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.