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When to Plant Kabocha in Clearwater County, ID

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.

Clearwater County, Idaho is in USDA Zone 5b. The average last spring frost is May 17 and the first fall frost is September 28, giving you a growing season of approximately 134 days.

At an elevation of 7,800 feet, Clearwater County receives approximately 19 inches of rainfall annually with predominantly loam soil. Summer highs average 87ยฐF, providing good warmth for Kabocha during the growing season. With low rainfall, drip irrigation is essential for growing Kabocha successfully. Mulch heavily to conserve soil moisture.

Clearwater County, ID (Zone 5b) Short season
134 days
Last Spring Frost May 17
134 growing days
First Fall Frost September 28

Clearwater County Soil Profile

Soil Type

Loam

Soil pH

6.5-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (1 days to spare)
Start indoors: Apr 3 Transplant: May 22 🍅 Harvest: Aug 21 – Sep 18
Recommended (50%) ✓ Fits season (1 days to spare)
Start indoors: Apr 12 Transplant: May 31 🍅 Harvest: Aug 30 – Sep 27
Safe Start (90%) ✓ Fits season (8 days to spare)
Start indoors: May 6 Transplant: Jun 24 🍅 Harvest: Sep 23 – Oct 21

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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.6″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 579 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” consider drought-tolerant varieties and mulching

Kabocha needs ~1,411 GDD — county provides 2,043 GDD Excellent fit

Kabocha Planting Timeline โ€” Clearwater County, ID

Kabocha Planting Calendar

Activity When Date Range
Start Indoors April 12 Apr 12 โ€“ Apr 26
Transplant Outdoors May 31 May 31 โ€“ Jun 14
Direct Sow May 24 May 24 โ€“ Jun 14
Harvest August 30 Aug 30 โ€“ Sep 27

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

85โ€“100 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 5b

Growing Season

134 days

Growing Tips for Clearwater County

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

Level Up Your Garden

Frequently Asked Questions

When should I plant Kabocha in Clearwater County, ID?

Clearwater County is in Zone 5b with an average last frost of May 17. Plan your Kabocha planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Clearwater County, ID?

Clearwater County, Idaho is in USDA Hardiness Zone 5b. The average last spring frost is May 17 and first fall frost is September 28.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Clearwater County gardeners in Zone 5b 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 Clearwater County, ID. Local conditions may vary. Last updated: April 2026.