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When to Plant Kabocha in Clallam County, WA

Kabocha is a Japanese winter squash with an exceptionally sweet, dense, chestnut-like flesh and dark green skin. It is a favorite in Asian cuisine for its rich, dry texture.

Clallam County, Washington is in USDA Zone 8a. 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 83ยฐF, so choose short-season varieties of Kabocha to ensure they mature before fall. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Kabocha root diseases.

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

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 (54 days to spare)
Start indoors: Mar 17 Transplant: Apr 28 🍅 Harvest: Jul 28 – Aug 25
Recommended (50%) ✓ Fits season (53 days to spare)
Start indoors: Mar 26 Transplant: May 7 🍅 Harvest: Aug 6 – Sep 3
Safe Start (90%) ✓ Fits season (51 days to spare)
Start indoors: Apr 11 Transplant: May 23 🍅 Harvest: Aug 22 – Sep 19

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 Kabocha's growing requirements.

Soil pH

Your soil pH (5.7โ€“6.8) overlaps with Kabocha's range (6.0โ€“7.5), though not a perfect match.

Soil Texture

The silt loam soil in Clallam County is excellent for Kabocha โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.8%) โ€” Kabocha will thrive.

How to Plant Kabocha

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

Plant Water Budget

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

Monthly Watering Guide for Kabocha

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

Month Kabocha Needs Rainfall You Supplement Action
Jan โ€” 8.9" 0" โ„๏ธ Dormant
Feb โ€” 5.5" 0" โ„๏ธ Dormant
Mar โ€” 5.3" 0" โ„๏ธ Dormant
Apr 4.3" 4.6" 0" โœ… Rainfall sufficient
May 4.3" 3" 1.3" ๐Ÿ’ง Light watering
Jun 4.3" 2.1" 2.2" ๐Ÿšฟ Regular watering
Jul 4.3" 0.8" 3.5" ๐Ÿšฟ Regular watering
Aug 4.3" 1.1" 3.2" ๐Ÿšฟ Regular watering
Sep 4.3" 2.5" 1.8" ๐Ÿ’ง Light watering
Oct 4.3" 4" 0.3" ๐Ÿ’ง Light watering
Nov โ€” 9.1" 0" โ„๏ธ Dormant
Dec โ€” 7.9" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Clallam County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Kabocha 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" โ€” every day above 50ยฐF 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.

Kabocha needs ~1,133 GDD — county provides 2,278 GDD Excellent fit

Kabocha Planting Timeline โ€” Clallam County, WA

Kabocha Planting Calendar

Activity When Date Range
Start Indoors March 26 Mar 26 โ€“ Apr 9
Transplant Outdoors May 7 May 7 โ€“ May 21
Direct Sow April 30 Apr 30 โ€“ May 21
Harvest August 6 Aug 6 โ€“ Sep 3

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

85โ€“100 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 8a

๐Ÿ“† Growing Season

186 days in Clallam County

Growing Tips for Kabocha in Clallam County

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

Common pests for Kabocha 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 after frost or start indoors. Harvest when the skin is hard and dull. The stem should be dry and corky. Stores well for 3-4 months in a cool, dry place.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Kabocha in Clallam County, WA?

Clallam County is in Zone 8a with an average last frost of April 23. Plan your Kabocha planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Clallam County, WA?

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

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Clallam County gardeners in Zone 8a organize planting dates, track what's growing, and never miss a planting window.

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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: April 2026.