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When to Plant Kabocha in Tuolumne County, CA

Tuolumne County, California Zone 9b May

Your May game plan for Tuolumne County, California

May is a pivotal month for Tuolumne County, California gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 25
Avg. first frost October 27
Soil temp (4") 62°F
Watering Critical
Pest pressure Moderate
Daylight 14.1 hrs
  1. Transplant kabocha outside

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

  2. Get kabocha seeds going inside

    Starting these indoors now means sturdy transplants ready the moment your soil warms up.

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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.

Tuolumne County, California is in USDA Zone 9b. The average last spring frost is April 25 and the first fall frost is October 27, giving you a growing season of approximately 185 days.

At an elevation of 2,990 feet, Tuolumne County receives approximately 37.7 inches of rainfall annually with predominantly loam soil. Summer highs average 88°F, providing good warmth for Kabocha during the growing season.

Tuolumne County, CA (Zone 9b) Moderate season
185 days
Last Spring Frost April 25
185 growing days
First Fall Frost October 27

Tuolumne County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (30 days to spare)
Start indoors: Mar 17 Transplant: Apr 21 🍅 Harvest: Jul 21 – Aug 18
Recommended (50%) ✓ Fits season (59 days to spare)
Start indoors: Mar 28 Transplant: May 2 🍅 Harvest: Aug 1 – Aug 29
Safe Start (90%) ✓ Fits season (24 days to spare)
Start indoors: May 23 Transplant: Jun 27 🍅 Harvest: Sep 26 – Oct 24

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 Tuolumne County

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

Soil pH

Your soil pH (6.6–7.5) is within Kabocha's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). 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
0.9″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 285 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 7.8" 0" ❄️ Dormant
Feb 8.2" 0" ❄️ Dormant
Mar 6.7" 0" ❄️ Dormant
Apr 4.3" 2.8" 1.5" 💧 Light watering
May 4.3" 1.1" 3.2" 🚿 Regular watering
Jun 4.3" 0.2" 4.1" 🚿 Regular watering
Jul 4.3" 0" 4.3" 🚿 Regular watering
Aug 4.3" 0" 4.3" 🚿 Regular watering
Sep 4.3" 0.4" 3.9" 🚿 Regular watering
Oct 4.3" 1.5" 2.8" 🚿 Regular watering
Nov 3" 0" ❄️ Dormant
Dec 6.1" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Tuolumne 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 ~1,480 GDD — county provides 2,960 GDD Excellent fit

Kabocha Planting Timeline — Tuolumne County, CA

Kabocha Planting Calendar

Activity When Date Range
Start Indoors March 28 Mar 28 – Apr 11
Transplant Outdoors May 2 May 2 – May 16
Direct Sow April 25 Apr 25 – May 16
Harvest August 1 Aug 1 – Aug 29

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
October
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: ideal

🗺️ USDA Zone

Zone 9b

📆 Growing Season

185 days in Tuolumne County

Growing Tips for Kabocha in Tuolumne County

Direct sow Kabocha outdoors after April 25 in Tuolumne 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 Tuolumne County, CA?

Tuolumne County is in Zone 9b with an average last frost of April 25. Plan your Kabocha planting based on this frost date — see the calendar above for exact timing.

What planting zone is Tuolumne County, CA?

Tuolumne County, California is in USDA Hardiness Zone 9b. The average last spring frost is April 25 and first fall frost is October 27.

🌱

Your Tuolumne County Garden Planner — Free

A 24-page printable planner built for Tuolumne County (Zone 9b). 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 Tuolumne County, CA. 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.