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When to Plant Kabocha in Greene County, IL

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.

Greene County, Illinois is in USDA Zone 5b. The average last spring frost is April 13 and the first fall frost is October 21, giving you a growing season of approximately 191 days.

At an elevation of 1,248 feet, Greene County receives approximately 37 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86ยฐF, providing good warmth for Kabocha during the growing season.

Greene County, IL (Zone 5b) Moderate season
191 days
Last Spring Frost April 13
191 growing days
First Fall Frost October 21

Greene County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (57 days to spare)
Start indoors: Mar 3 Transplant: Apr 21 🍅 Harvest: Jul 21 – Aug 18
Recommended (50%) ✓ Fits season (58 days to spare)
Start indoors: Mar 9 Transplant: Apr 27 🍅 Harvest: Jul 27 – Aug 24
Safe Start (90%) ✓ Fits season (57 days to spare)
Start indoors: Mar 21 Transplant: May 9 🍅 Harvest: Aug 8 – Sep 5

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 Greene County

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

Soil pH

Your soil pH (6.1โ€“6.7) is within Kabocha's preferred range (6.0โ€“7.5).

Soil Texture

The silt loam soil in Greene County is excellent for Kabocha โ€” good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Kabocha.

Organic Matter

Organic matter is excellent (4.5%) โ€” 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
0.8″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 992 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” 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 โ€” 1.6" 0" โ„๏ธ Dormant
Feb โ€” 1.7" 0" โ„๏ธ Dormant
Mar โ€” 2.7" 0" โ„๏ธ Dormant
Apr 4.3" 3.2" 1.1" ๐Ÿ’ง Light watering
May 4.3" 3.9" 0.4" ๐Ÿ’ง Light watering
Jun 4.3" 4.5" 0" โœ… Rainfall sufficient
Jul 4.3" 3.9" 0.4" ๐Ÿ’ง Light watering
Aug 4.3" 4.4" 0" โœ… Rainfall sufficient
Sep 4.3" 3.3" 1" ๐Ÿ’ง Light watering
Oct 4.3" 3" 1.3" ๐Ÿ’ง Light watering
Nov โ€” 2.6" 0" โ„๏ธ Dormant
Dec โ€” 2.2" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Greene County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~1,341 GDD — county provides 2,769 GDD Excellent fit

Kabocha Planting Timeline โ€” Greene County, IL

Kabocha Planting Calendar

Activity When Date Range
Start Indoors March 9 Mar 9 โ€“ Mar 23
Transplant Outdoors April 27 Apr 27 โ€“ May 11
Direct Sow April 20 Apr 20 โ€“ May 11
Harvest July 27 Jul 27 โ€“ Aug 24

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

85โ€“100 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 5b

๐Ÿ“† Growing Season

191 days in Greene County

Growing Tips for Kabocha in Greene County

Direct sow Kabocha outdoors after April 13 in Greene 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 Greene County, IL?

Greene County is in Zone 5b with an average last frost of April 13. Plan your Kabocha planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Greene County, IL?

Greene County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 13 and first fall frost is October 21.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Greene 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 Greene County, IL. Local conditions may vary. Last updated: April 2026.