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When to Plant Hubbard Squash in Skamania County, WA

Skamania County, Washington Zone 8a May

May to-do list for Skamania County, Washington

Each item below is timed to Skamania County, Washington's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 18
Avg. first frost October 19
Soil temp (4") 65°F
Watering High
Pest pressure Moderate
Daylight 14.8 hrs
  1. Plant out hubbard squash

    Your last frost (April 18) has passed. These warm-season crops can handle outdoor soil now.

  2. Time to start hubbard squash inside

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

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Hubbard squash is a large, bumpy-skinned winter squash with dense, sweet, dry flesh ideal for baking and pies. The hard shell allows storage for 6 months or more.

Skamania County, Washington is in USDA Zone 8a. The average last spring frost is April 18 and the first fall frost is October 19, giving you a growing season of approximately 184 days.

At an elevation of 16 feet, Skamania County receives approximately 43 inches of rainfall annually with predominantly silt loam soil. Summer highs average 79°F, so choose short-season varieties of Hubbard Squash to ensure they mature before fall.

Skamania County, WA (Zone 8a) Moderate season
184 days
Last Spring Frost April 18
184 growing days
First Fall Frost October 19

Skamania County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (28 days to spare)
Start indoors: Mar 15 Transplant: Apr 26 🍅 Harvest: Aug 9 – Sep 13
Recommended (50%) ✓ Fits season (30 days to spare)
Start indoors: Mar 21 Transplant: May 2 🍅 Harvest: Aug 15 – Sep 19
Safe Start (90%) ✓ Fits season (38 days to spare)
Start indoors: Apr 12 Transplant: May 24 🍅 Harvest: Sep 6 – Oct 11

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 Skamania County

How your county's soil matches Hubbard Squash's growing requirements.

Soil pH

Your soil pH (5.6–6.2) is more acidic than Hubbard Squash prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.0%) — Hubbard Squash will thrive.

How to Plant Hubbard Squash

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 30 gal / 100 sq ft

Monthly Watering Guide for Hubbard Squash

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

Month Hubbard Squash Needs Rainfall You Supplement Action
Jan 6.5" 0" ❄️ Dormant
Feb 4.3" 0" ❄️ Dormant
Mar 3.8" 0" ❄️ Dormant
Apr 4.3" 3.6" 0.7" 💧 Light watering
May 4.3" 2.1" 2.2" 🚿 Regular watering
Jun 4.3" 1.7" 2.6" 🚿 Regular watering
Jul 4.3" 0.7" 3.6" 🚿 Regular watering
Aug 4.3" 0.7" 3.6" 🚿 Regular watering
Sep 4.3" 1.8" 2.5" 🚿 Regular watering
Oct 4.3" 3.3" 1" 💧 Light watering
Nov 7.4" 0" ❄️ Dormant
Dec 7.1" 0" ❄️ Dormant

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

Hubbard Squash 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.

Hubbard Squash needs ~1,018 GDD — county provides 1,702 GDD Excellent fit

Hubbard Squash Planting Timeline — Skamania County, WA

Hubbard Squash Planting Calendar

Activity When Date Range
Start Indoors March 21 Mar 21 – Apr 4
Transplant Outdoors May 2 May 2 – May 16
Direct Sow April 25 Apr 25 – May 16
Harvest August 15 Aug 15 – Sep 19

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

100–120 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 8a

📆 Growing Season

184 days in Skamania County

Growing Tips for Hubbard Squash in Skamania County

Direct sow Hubbard Squash outdoors after April 18 in Skamania County when soil has warmed and frost danger has passed.

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

General growing tips

Start seeds indoors in short-season areas. Requires ample space and rich soil. Harvest when the skin is very hard and the color is deep. Cure in the sun before storing.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Hubbard Squash in Skamania County, WA?

Skamania County is in Zone 8a with an average last frost of April 18. Plan your Hubbard Squash planting based on this frost date — see the calendar above for exact timing.

What planting zone is Skamania County, WA?

Skamania County, Washington is in USDA Hardiness Zone 8a. The average last spring frost is April 18 and first fall frost is October 19.

🌱

Your Skamania County Garden Planner — Free

A 24-page printable planner built for Skamania 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 Skamania 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.