Blog

When to Plant Pumpkin in Wahkiakum County, WA

Wahkiakum County, Washington Zone 8b May

May to-do list for Wahkiakum County, Washington

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

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. Start pumpkin indoors

    Your window is short. These crops want several weeks of indoor growth before they go outside.

Instant PDF download. No spam, unsubscribe any time.

Pumpkins are large-fruited squash varieties grown for eating, decoration, and seed production. They require ample space and a long, warm growing season.

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 Pumpkin 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
Share this guide:

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 (56 days to spare)
Start indoors: Mar 5 Transplant: Apr 16 🍅 Harvest: Jul 16 – Sep 3
Recommended (50%) ✓ Fits season (51 days to spare)
Start indoors: Mar 16 Transplant: Apr 27 🍅 Harvest: Jul 27 – Sep 14
Safe Start (90%) ✓ Fits season (63 days to spare)
Start indoors: Apr 2 Transplant: May 14 🍅 Harvest: Aug 13 – Oct 1

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 Pumpkin's growing requirements.

Soil pH

Your soil pH (5.4–6.3) is more acidic than Pumpkin prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

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

How to Plant Pumpkin

1"
Planting Depth
30"
Between Plants
42"
Between Rows

Plant Water Budget

Plant needs
1.3″/week
Rainfall provides
0.7″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 1,052 gal / 100 sq ft

Monthly Watering Guide for Pumpkin

Pumpkin needs approximately 1.3 inches of water per week (5.6" per month). Here's how your county's rainfall compares month by month.

Month Pumpkin Needs Rainfall You Supplement Action
Jan 4.9" 0" ❄️ Dormant
Feb 4.2" 0" ❄️ Dormant
Mar 3.6" 0" ❄️ Dormant
Apr 5.6" 2.6" 3" 🚿 Regular watering
May 5.6" 1.8" 3.8" 🚿 Regular watering
Jun 5.6" 1.4" 4.2" 🚿 Regular watering
Jul 5.6" 0.6" 5" 🚿 Regular watering
Aug 5.6" 0.7" 4.9" 🚿 Regular watering
Sep 5.6" 1.4" 4.2" 🚿 Regular watering
Oct 5.6" 2.9" 2.7" 💧 Light watering
Nov 5.6" 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.

Pumpkin 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.

Pumpkin needs ~1,409 GDD — county provides 2,818 GDD Excellent fit

Pumpkin Planting Timeline — Wahkiakum County, WA

Pumpkin Planting Calendar

Activity When Date Range
Start Indoors March 16 Mar 16 – Mar 30
Transplant Outdoors April 27 Apr 27 – May 11
Direct Sow April 20 Apr 20 – May 11
Harvest July 27 Jul 27 – Sep 14

Plant 1" deep · 30" apart · Rows 42" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June
July Harvest
August Harvest
September Harvest
October
November
December
Share this guide:

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.3"/week · 1-2 times/week

📅 Days to Maturity

85–120 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 8b

📆 Growing Season

205 days in Wahkiakum County

Growing Tips for Pumpkin in Wahkiakum County

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

Common pests for Pumpkin in this region include squash vine borer and cucumber beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow on mounds after last frost. Allow 6-10 feet between plants. Slip a board under developing fruit to prevent rot. Harvest when rind is hard and deep in color.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Pumpkin in Wahkiakum County, WA?

Wahkiakum County is in Zone 8b with an average last frost of April 13. Plan your Pumpkin 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.

🌱

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.

Instant PDF download. No spam, unsubscribe any time.

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.