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When to Plant Kabocha in Clear Creek County, CO

Clear Creek County, Colorado Zone 4b April

Your April game plan for Clear Creek County, Colorado

If you only do a handful of things in the garden this April, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 14
Avg. first frost September 26
Soil temp (4") 23°F
Watering High
Pest pressure Low
Daylight 13.1 hrs
May will be here before you know it — start on
  • Direct-sowing: kabocha

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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.

Clear Creek County, Colorado is in USDA Zone 4b. The average last spring frost is May 14 and the first fall frost is September 26, giving you a growing season of approximately 135 days.

At an elevation of 6,538 feet, Clear Creek County receives approximately 24.6 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Kabocha to ensure they mature before fall.

Clear Creek County, CO (Zone 4b) Short season
135 days
Last Spring Frost May 14
135 growing days
First Fall Frost September 26

Clear Creek County Soil Profile

Soil Type

Loam

Soil pH

6.8-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (0 days to spare)
Start indoors: Mar 22 Transplant: May 24 🍅 Harvest: Aug 23 – Sep 20
Recommended (50%) ✗ May not fit
Start indoors: Apr 2 Transplant: Jun 4 🍅 Harvest: Sep 3 – Oct 1
Safe Start (90%) ✗ May not fit
Start indoors: Apr 29 Transplant: Jul 1 🍅 Harvest: Sep 30 – Oct 28

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 Clear Creek County

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

Soil pH

Your soil pH (6.8–8.1) overlaps with Kabocha's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in Clear Creek County is excellent for Kabocha — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.2%). Annual compost additions will help Kabocha.

How to Plant Kabocha

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 338 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

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 1.9" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2.7" 0" ❄️ Dormant
May 4.3" 2.7" 1.6" 💧 Light watering
Jun 4.3" 1.7" 2.6" 🚿 Regular watering
Jul 4.3" 2.4" 1.9" 💧 Light watering
Aug 4.3" 2.4" 1.9" 💧 Light watering
Sep 4.3" 2.1" 2.2" 🚿 Regular watering
Oct 2.3" 0" ❄️ Dormant
Nov 1.9" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Clear Creek County). Supplement amounts are based on average rainfall — 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" — 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.

Kabocha needs ~1,133 GDD — county provides 1,653 GDD Excellent fit

Kabocha Planting Timeline — Clear Creek County, CO

Kabocha Planting Calendar

Activity When Date Range
Start Indoors April 2 Apr 2 – Apr 16
Transplant Outdoors June 4 Jun 4 – Jun 18
Direct Sow May 28 May 28 – Jun 18
Harvest September 3 Sep 3 – Oct 1

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

85–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 4b

📆 Growing Season

135 days in Clear Creek County

Growing Tips for Kabocha in Clear Creek County

Direct sow Kabocha outdoors after May 14 in Clear Creek 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.

Clear Creek County receives only 25" of rain annually. Kabocha needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Clear Creek County, CO?

Clear Creek County is in Zone 4b with an average last frost of May 14. Plan your Kabocha planting based on this frost date — see the calendar above for exact timing.

What planting zone is Clear Creek County, CO?

Clear Creek County, Colorado is in USDA Hardiness Zone 4b. The average last spring frost is May 14 and first fall frost is September 26.

🌱

Your Clear Creek County Garden Planner — Free

A 24-page printable planner built for Clear Creek County (Zone 4b). 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 Clear Creek County, CO. Local conditions may vary. Last updated: April 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.