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When to Plant Microgreens in Wahkiakum County, WA

Wahkiakum County, Washington Zone 8b May

This month in Wahkiakum County, Washington

Here's what deserves your attention in Wahkiakum County, Washington this month. Everything below is tailored to Zone 8b and timed around your local frost dates.

Avg. last frost April 13
Avg. first frost November 4
Soil temp (4") 69°F
Watering High
Pest pressure High
Daylight 14.8 hrs
  1. Time to start microgreens inside

    You're about 25 weeks out from your last frost — the perfect window to get these germinating indoors.

  2. Pick microgreens

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

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Microgreens are young seedlings of vegetables and herbs harvested at the cotyledon or first true leaf stage. They pack concentrated flavors and nutrients in a tiny package.

Wahkiakum County, Washington is in USDA Zone 8b. The average last spring frost is April 13 and the first fall frost is November 4, giving you a growing season of approximately 205 days.

At an elevation of 180 feet, Wahkiakum County receives approximately 35.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Microgreens during the growing season.

Wahkiakum County, WA (Zone 8b) Long season
205 days
Last Spring Frost April 13
205 growing days
First Fall Frost November 4
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Wahkiakum County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (175 days to spare)
Start indoors: Feb 26 Transplant: Apr 2 🍅 Harvest: Apr 9 – May 7
Recommended (50%) ✓ Fits season (170 days to spare)
Start indoors: Mar 9 Transplant: Apr 13 🍅 Harvest: Apr 20 – May 18
Safe Start (90%) ✓ Fits season (182 days to spare)
Start indoors: Mar 26 Transplant: Apr 30 🍅 Harvest: May 7 – Jun 4

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 Wahkiakum County

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

Soil pH

Your soil pH (5.4–6.3) is more acidic than Microgreens prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.6%) — Microgreens will thrive.

How to Plant Microgreens

0.5"
Planting Depth
2"
Between Plants
6"
Between Rows

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

Succession Planting Microgreens

40
successive plantings in your 205-day season

Sow every 0.7 weeks. Last sowing by Oct 14 to harvest before frost.

For a dedicated fall crop, sow by Aug 26.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 505 gal / 100 sq ft

Monthly Watering Guide for Microgreens

Microgreens needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Microgreens Needs Rainfall You Supplement Action
Jan 4.9" 0" ❄️ Dormant
Feb 4.2" 0" ❄️ Dormant
Mar 3.6" 0" ❄️ Dormant
Apr 4.3" 2.6" 1.7" 💧 Light watering
May 4.3" 1.8" 2.5" 🚿 Regular watering
Jun 4.3" 1.4" 2.9" 🚿 Regular watering
Jul 4.3" 0.6" 3.7" 🚿 Regular watering
Aug 4.3" 0.7" 3.6" 🚿 Regular watering
Sep 4.3" 1.4" 2.9" 🚿 Regular watering
Oct 4.3" 2.9" 1.4" 💧 Light watering
Nov 4.3" 5.8" 0" ✅ Rainfall sufficient
Dec 5.3" 0" ❄️ Dormant

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

Microgreens 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.

Microgreens needs ~192 GDD — county provides 2,818 GDD Excellent fit

Microgreens Planting Timeline — Wahkiakum County, WA

Microgreens Planting Calendar

Activity When Date Range
Start Indoors March 9 Mar 9 – Mar 23
Transplant Outdoors April 13 Apr 13 – Apr 27
Direct Sow March 30 Mar 30 – Apr 20
Harvest April 20 Apr 20 – May 18
Fall Sowing August 26 Aug 26 – Sep 9

Plant 0.5" deep · 2" apart · Rows 6" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors Direct Sow
April Transplant Outdoors Direct Sow Harvest
May Harvest
June
July
August Fall Sowing
September Fall Sowing
October
November
December
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Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

7–21 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 8b

📆 Growing Season

205 days in Wahkiakum County

Growing Tips for Microgreens in Wahkiakum County

Direct sow Microgreens outdoors after April 13 in Wahkiakum County when soil has warmed and frost danger has passed.

Your generous 205.0-day season in Wahkiakum County allows multiple plantings of Microgreens. Sow every 3.0 days for continuous harvest.

General growing tips

Sow seeds densely on shallow trays of moist growing medium. Cover until germination, then provide light. Harvest with scissors when 1-3 inches tall. Grow year-round indoors.

Frequently Asked Questions

When should I plant Microgreens in Wahkiakum County, WA?

Wahkiakum County is in Zone 8b with an average last frost of April 13. Plan your Microgreens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Wahkiakum County, WA?

Wahkiakum County, Washington is in USDA Hardiness Zone 8b. The average last spring frost is April 13 and first fall frost is November 4.

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Your Wahkiakum County Garden Planner — Free

A 24-page printable planner built for Wahkiakum 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 Wahkiakum 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.