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When to Plant Kabocha in Ottawa County, OH

Ottawa County, Ohio Zone 6b May

What to do in May

A quick May briefing for Ottawa County, Ohio gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 25
Avg. first frost October 25
Soil temp (4") 63°F
Watering Low
Pest pressure Low
Daylight 14.3 hrs
  1. Plant out kabocha

    Frost risk is low now in Ottawa County, Ohio. If you've been covering beds overnight, you can stop.

  2. Scatter kabocha into prepared beds

    Mark the row. Birds and stray feet both have opinions about unmarked beds.

  3. Start kabocha under lights

    You're about 24 weeks out from your last frost — the perfect window to get these germinating indoors.

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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.

Ottawa County, Ohio is in USDA Zone 6b. The average last spring frost is April 25 and the first fall frost is October 25, giving you a growing season of approximately 183 days.

At an elevation of 1,264 feet, Ottawa County receives approximately 31.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Kabocha during the growing season.

Ottawa County, OH (Zone 6b) Moderate season
183 days
Last Spring Frost April 25
183 growing days
First Fall Frost October 25

Ottawa County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (49 days to spare)
Start indoors: Mar 14 Transplant: May 2 🍅 Harvest: Aug 1 – Aug 29
Recommended (50%) ✓ Fits season (50 days to spare)
Start indoors: Mar 21 Transplant: May 9 🍅 Harvest: Aug 8 – Sep 5
Safe Start (90%) ✓ Fits season (50 days to spare)
Start indoors: Mar 29 Transplant: May 17 🍅 Harvest: Aug 16 – Sep 13

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 Ottawa County

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

Soil pH

Your soil pH (6.2–7.0) is within Kabocha's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is excellent (5.1%) — 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
0.7″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 466 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 1.4" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 4.3" 3.2" 1.1" 💧 Light watering
May 4.3" 3.9" 0.4" 💧 Light watering
Jun 4.3" 3.9" 0.4" 💧 Light watering
Jul 4.3" 3.3" 1" 💧 Light watering
Aug 4.3" 2.9" 1.4" 💧 Light watering
Sep 4.3" 3.1" 1.2" 💧 Light watering
Oct 4.3" 2.2" 2.1" 💧 Light watering
Nov 2.2" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Ottawa 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 2,928 GDD Excellent fit

Kabocha Planting Timeline — Ottawa County, OH

Kabocha Planting Calendar

Activity When Date Range
Start Indoors March 21 Mar 21 – Apr 4
Transplant Outdoors May 9 May 9 – May 23
Direct Sow May 2 May 2 – May 23
Harvest August 8 Aug 8 – Sep 5

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors
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

85–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 6b

📆 Growing Season

183 days in Ottawa County

Growing Tips for Kabocha in Ottawa County

Direct sow Kabocha outdoors after April 25 in Ottawa 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 Ottawa County, OH?

Ottawa County is in Zone 6b 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 Ottawa County, OH?

Ottawa County, Ohio is in USDA Hardiness Zone 6b. The average last spring frost is April 25 and first fall frost is October 25.

🌱

Your Ottawa County Garden Planner — Free

A 24-page printable planner built for Ottawa County (Zone 6b). 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 Ottawa County, OH. 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.