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When to Plant Mustard Greens in Clallam County, WA

Clallam County, Washington Zone 8b May

Your May game plan for Clallam County, Washington

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

Avg. last frost April 23
Avg. first frost October 26
Soil temp (4") 70°F
Watering Moderate
Pest pressure High
Daylight 15 hrs
  1. Start mustard greens under lights

    Starting these indoors now means sturdy transplants ready the moment your soil warms up.

  2. Harvest mustard greens as they ripen

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

Get ahead of June
  • First harvests: mustard greens

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Mustard greens are fast-growing brassicas with a spicy, peppery kick. They come in green, red, and purple varieties and are excellent cooked or in salads.

Clallam County, Washington is in USDA Zone 8b. The average last spring frost is April 23 and the first fall frost is October 26, giving you a growing season of approximately 186 days.

At an elevation of 194 feet, Clallam County receives approximately 54.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Mustard Greens to ensure they mature before fall. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Mustard Greens root diseases.

Clallam County, WA (Zone 8b) Moderate season
186 days
Last Spring Frost April 23
186 growing days
First Fall Frost October 26
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Clallam County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (89 days to spare)
Start indoors: Mar 10 Transplant: Apr 14 🍅 Harvest: May 19 – Jul 21
Recommended (50%) ✓ Fits season (88 days to spare)
Start indoors: Mar 19 Transplant: Apr 23 🍅 Harvest: May 28 – Jul 30
Safe Start (90%) ✓ Fits season (86 days to spare)
Start indoors: Apr 4 Transplant: May 9 🍅 Harvest: Jun 13 – Aug 15

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 Clallam County

How your county's soil matches Mustard Greens's growing requirements.

Soil pH

Your soil pH (5.7–6.8) overlaps with Mustard Greens's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.8%) — Mustard Greens will thrive.

How to Plant Mustard Greens

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Mustard Greens

7
successive plantings in your 186-day season

Sow every 3.4 weeks. Last sowing by Sep 06 to harvest before frost.

For a dedicated fall crop, sow by Aug 17.

Plant 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 Mustard Greens

Mustard Greens needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Mustard Greens Needs Rainfall You Supplement Action
Jan 8.9" 0" ❄️ Dormant
Feb 5.5" 0" ❄️ Dormant
Mar 5.3" 0" ❄️ Dormant
Apr 3" 4.6" 0" ✅ Rainfall sufficient
May 3" 3" 0" ✅ Rainfall sufficient
Jun 3" 2.1" 0.9" 💧 Light watering
Jul 3" 0.8" 2.2" 🚿 Regular watering
Aug 3" 1.1" 1.9" 🚿 Regular watering
Sep 3" 2.5" 0.5" 💧 Light watering
Oct 3" 4" 0" ✅ Rainfall sufficient
Nov 9.1" 0" ❄️ Dormant
Dec 7.9" 0" ❄️ Dormant

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

Mustard Greens 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.

Mustard Greens needs ~490 GDD — county provides 2,278 GDD Excellent fit

Mustard Greens Planting Timeline — Clallam County, WA

Mustard Greens Planting Calendar

Activity When Date Range
Start Indoors March 19 Mar 19 – Apr 2
Transplant Outdoors April 23 Apr 23 – May 7
Direct Sow April 9 Apr 9 – Apr 30
Harvest May 28 May 28 – Jul 30
Fall Sowing August 17 Aug 17 – Aug 31

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Transplant Outdoors Direct Sow
May Transplant Outdoors Harvest
June Harvest
July Harvest
August Fall Sowing
September
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

30–50 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 8b

📆 Growing Season

186 days in Clallam County

Growing Tips for Mustard Greens in Clallam County

Direct sow Mustard Greens outdoors after April 23 in Clallam County when soil has warmed and frost danger has passed.

Your generous 186.0-day season in Clallam County allows multiple plantings of Mustard Greens. Sow every 15.0 days for continuous harvest.

Common pests for Mustard Greens in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow in early spring or fall. Harvest young leaves for milder flavor. Plants bolt quickly in heat so grow as a cool-season crop or provide shade.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Mustard Greens in Clallam County, WA?

Clallam County is in Zone 8b with an average last frost of April 23. Plan your Mustard Greens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Clallam County, WA?

Clallam County, Washington is in USDA Hardiness Zone 8b. The average last spring frost is April 23 and first fall frost is October 26.

🌱

Your Clallam County Garden Planner — Free

A 24-page printable planner built for Clallam 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 Clallam 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.