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When to Plant Kabocha in Morris County, NJ

Morris County, New Jersey Zone 6b May

Morris County, New Jersey gardeners: here's your May plan

Welcome to May in Zone 6b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost March 29
Avg. first frost November 12
Soil temp (4") 61°F
Watering Moderate
Pest pressure Low
Daylight 14.3 hrs
  1. Start kabocha indoors

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

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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.

Morris County, New Jersey is in USDA Zone 6b. The average last spring frost is March 29 and the first fall frost is November 12, giving you a growing season of approximately 228 days.

At an elevation of 227 feet, Morris County receives approximately 40.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Kabocha during the growing season.

Morris County, NJ (Zone 6b) Long season
228 days
Last Spring Frost March 29
228 growing days
First Fall Frost November 12

Morris County Soil Profile

Soil Type

Silt Loam

Soil pH

5.1-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (95 days to spare)
Start indoors: Feb 18 Transplant: Apr 8 🍅 Harvest: Jul 8 – Aug 5
Recommended (50%) ✓ Fits season (95 days to spare)
Start indoors: Feb 22 Transplant: Apr 12 🍅 Harvest: Jul 12 – Aug 9
Safe Start (90%) ✓ Fits season (104 days to spare)
Start indoors: Mar 5 Transplant: Apr 23 🍅 Harvest: Jul 23 – Aug 20

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 Morris County

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

Soil pH

Your soil pH (5.1–6.5) is more acidic than Kabocha prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.8%). 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
0.8″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 504 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 3.1" 0" ❄️ Dormant
Feb 2.6" 0" ❄️ Dormant
Mar 4.3" 3.9" 0.4" 💧 Light watering
Apr 4.3" 3.1" 1.2" 💧 Light watering
May 4.3" 3.2" 1.1" 💧 Light watering
Jun 4.3" 4.1" 0.2" 💧 Light watering
Jul 4.3" 4.7" 0" ✅ Rainfall sufficient
Aug 4.3" 3.7" 0.6" 💧 Light watering
Sep 4.3" 3.5" 0.8" 💧 Light watering
Oct 4.3" 3.1" 1.2" 💧 Light watering
Nov 4.3" 3" 1.3" 💧 Light watering
Dec 2.8" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Morris 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 ~1,688 GDD — county provides 4,161 GDD Excellent fit

Kabocha Planting Timeline — Morris County, NJ

Kabocha Planting Calendar

Activity When Date Range
Start Indoors February 22 Feb 22 – Mar 8
Transplant Outdoors April 12 Apr 12 – Apr 26
Direct Sow April 5 Apr 5 – Apr 26
Harvest July 12 Jul 12 – Aug 9

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors
April Transplant Outdoors Direct Sow
May
June
July Harvest
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: too_acidic

🗺️ USDA Zone

Zone 6b

📆 Growing Season

228 days in Morris County

Growing Tips for Kabocha in Morris County

Direct sow Kabocha outdoors after March 29 in Morris 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 Morris County, NJ?

Morris County is in Zone 6b with an average last frost of March 29. Plan your Kabocha planting based on this frost date — see the calendar above for exact timing.

What planting zone is Morris County, NJ?

Morris County, New Jersey is in USDA Hardiness Zone 6b. The average last spring frost is March 29 and first fall frost is November 12.

🌱

Your Morris County Garden Planner — Free

A 24-page printable planner built for Morris 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 Morris County, NJ. 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.