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When to Plant Oregano in Garfield County, WA

Oregano is a robust perennial herb essential to Italian and Greek cuisine. Its pungent, savory leaves intensify in flavor when dried.

Garfield County, Washington is in USDA Zone 6a. The average last spring frost is May 9 and the first fall frost is September 30, giving you a growing season of approximately 144 days.

At an elevation of 3,226 feet, Garfield County receives approximately 17.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88ยฐF, providing good warmth for Oregano during the growing season. With low rainfall, drip irrigation is essential for growing Oregano successfully. Mulch heavily to conserve soil moisture.

Garfield County, WA (Zone 6a) Short season
144 days
Last Spring Frost May 9
144 growing days
First Fall Frost September 30

Garfield County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (6 days to spare)
Transplant: May 5 🍅 Harvest: Jul 7 – Sep 15
Recommended (50%) ✓ Fits season (4 days to spare)
Transplant: May 16 🍅 Harvest: Jul 18 – Sep 26
Safe Start (90%) ✗ May not fit
Transplant: Jun 13 🍅 Harvest: Aug 15 – Oct 24

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 Garfield County

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

Soil pH

Your soil pH (5.6โ€“6.8) overlaps with Oregano's range (6.0โ€“8.0), though not a perfect match.

Soil Texture

The silt loam soil in Garfield County is excellent for Oregano โ€” good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Oregano.

Organic Matter

Organic matter is excellent (4.3%) โ€” Oregano will thrive.

How to Plant Oregano

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Oregano

2
successive plantings in your 144-day season

Sow every 6.9 weeks. Last sowing by Jul 02 to harvest before frost.

Plant Water Budget

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

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Monthly Watering Guide for Oregano

Oregano needs approximately 0.3 inches of water per week (1.3" per month). Here's how your county's rainfall compares month by month.

Month Oregano Needs Rainfall You Supplement Action
Jan โ€” 2.7" 0" โ„๏ธ Dormant
Feb โ€” 2" 0" โ„๏ธ Dormant
Mar โ€” 1.7" 0" โ„๏ธ Dormant
Apr โ€” 1.1" 0" โ„๏ธ Dormant
May 1.3" 1.1" 0.2" ๐Ÿ’ง Light watering
Jun 1.3" 0.6" 0.7" ๐Ÿšฟ Regular watering
Jul 1.3" 0.3" 1" ๐Ÿšฟ Regular watering
Aug 1.3" 0.3" 1" ๐Ÿšฟ Regular watering
Sep 1.3" 0.8" 0.5" ๐Ÿ’ง Light watering
Oct โ€” 1.4" 0" โ„๏ธ Dormant
Nov โ€” 3" 0" โ„๏ธ Dormant
Dec โ€” 2.5" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Garfield County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Oregano 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" โ€” every day above 50ยฐF 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.

Oregano needs ~1,200 GDD — county provides 2,304 GDD Excellent fit

Oregano Planting Timeline โ€” Garfield County, WA

Oregano Planting Calendar

Activity When Date Range
Transplant Outdoors May 16 May 16 โ€“ May 30
Harvest July 18 Jul 18 โ€“ Sep 26

Plant 0.5" deep ยท 8" apart ยท Rows 12" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May Transplant Outdoors
June โ€”
July Harvest
August Harvest
September Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.3"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

60โ€“90 days

๐Ÿงช Soil pH

Needs 6โ€“8 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 6a

๐Ÿ“† Growing Season

144 days in Garfield County

Growing Tips for Oregano in Garfield County

Direct sow Oregano outdoors after May 09 in Garfield County when soil has warmed and frost danger has passed.

General growing tips

Start from seed, cuttings, or divisions. Harvest just before flowering for strongest flavor. Cut plants back to a few inches in spring to encourage vigorous new growth.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Oregano in Garfield County, WA?

Garfield County is in Zone 6a with an average last frost of May 9. Plan your Oregano planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Garfield County, WA?

Garfield County, Washington is in USDA Hardiness Zone 6a. The average last spring frost is May 9 and first fall frost is September 30.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Garfield County gardeners in Zone 6a 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.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Garfield County, WA. Local conditions may vary. Last updated: April 2026.