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When to Plant Oregano in Whatcom County, WA

Oregano
Whatcom County, Washington Zone 8a August

August to-do list for Whatcom County, Washington

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

Avg. last frost April 6
Avg. first frost October 29
Soil temp (4") 84°F
Watering Critical
Pest pressure High
Daylight 14.2 hrs
  1. Start harvesting oregano

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

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

Whatcom County, Washington is in USDA Zone 8a. The average last spring frost is April 6 and the first fall frost is October 29, giving you a growing season of approximately 206 days.

At an elevation of 386 feet, Whatcom County receives approximately 49 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Oregano during the growing season.

Whatcom County, WA (Zone 8a) Long season
206 days
Last Spring Frost April 6
206 growing days
First Fall Frost October 29

Whatcom County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.4

Drainage

Well Drained

Oregano Planting Risk Windows

Early Start (70% safe) ✓ Fits season (69 days to spare)
Transplant: Apr 1 🍅 Harvest: Jun 3 – Aug 12
Recommended (50%) ✓ Fits season (66 days to spare)
Transplant: Apr 13 🍅 Harvest: Jun 15 – Aug 24
Safe Start (90%) ✓ Fits season (59 days to spare)
Transplant: May 13 🍅 Harvest: Jul 15 – Sep 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 Whatcom County

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

Soil pH

Your soil pH (5.2–6.4) is more acidic than Oregano prefers (6.0–8.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.7%) — Oregano will thrive.

How to Plant Oregano

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

Succession Planting Oregano

4
successive plantings in your 206-day season

Sow every 6.9 weeks. Last sowing by Jul 31 to harvest before frost.

Oregano Water Budget

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

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 6.1" 0" ❄️ Dormant
Feb 6.2" 0" ❄️ Dormant
Mar 4.3" 0" ❄️ Dormant
Apr 1.3" 3.8" 0" ✅ Rainfall sufficient
May 1.3" 3.1" 0" ✅ Rainfall sufficient
Jun 1.3" 2.1" 0" ✅ Rainfall sufficient
Jul 1.3" 0.7" 0.6" 💧 Light watering
Aug 1.3" 0.9" 0.4" 💧 Light watering
Sep 1.3" 2" 0" ✅ Rainfall sufficient
Oct 1.3" 4.5" 0" ✅ Rainfall sufficient
Nov 7.1" 0" ❄️ Dormant
Dec 8.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Whatcom County). Supplement amounts are based on average rainfall — 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" — 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.

Oregano needs ~1,031 GDD — county provides 2,832 GDD Excellent fit

Oregano Planting Timeline — Whatcom County, WA

Oregano Planting Calendar

Activity When Date Range
Transplant Outdoors April 13 Apr 13 – Apr 27
Harvest June 15 Jun 15 – Aug 24

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.3"/week · Natural rainfall sufficient

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–8 · Your soil: too_acidic

🗺️ USDA Zone

Zone 8a

📆 Growing Season

206 days in Whatcom County

Growing Tips for Oregano in Whatcom County

Direct sow Oregano outdoors after April 06 in Whatcom 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 Whatcom County, WA?

Whatcom County is in Zone 8a with an average last frost of April 6. Plan your Oregano planting based on this frost date — see the calendar above for exact timing.

What planting zone is Whatcom County, WA?

Whatcom County, Washington is in USDA Hardiness Zone 8a. The average last spring frost is April 6 and first fall frost is October 29.

🌱

Your Whatcom County Garden Planner — Free

A 22-page printable planner built for Whatcom County (Zone 8a). 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 Whatcom County, WA. Local conditions may vary. Last updated: August 2026.

Sources & credits

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