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When to Plant Kabocha in Jefferson County, AL

Jefferson County, Alabama Zone 8a May

May in Jefferson County, Alabama — your action list

Welcome to May in Zone 8a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost March 31
Avg. first frost October 31
Soil temp (4") 70°F
Watering Low
Pest pressure Moderate
Daylight 13.7 hrs

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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.

Jefferson County, Alabama is in USDA Zone 8a. The average last spring frost is March 31 and the first fall frost is October 31, giving you a growing season of approximately 214 days.

At an elevation of 408 feet, Jefferson County receives approximately 48 inches of rainfall annually with predominantly clay loam soil. Summer highs average 94°F, providing good warmth for Kabocha during the growing season. Clay soil retains moisture well for Kabocha, but amend with compost to improve drainage and prevent root rot.

Jefferson County, AL (Zone 8a) Long season
214 days
Last Spring Frost March 31
214 growing days
First Fall Frost October 31
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Jefferson County Soil Profile

Soil Type

Clay Loam

Soil pH

5.7-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (80 days to spare)
Start indoors: Feb 26 Transplant: Apr 9 🍅 Harvest: Jul 9 – Aug 6
Recommended (50%) ✓ Fits season (81 days to spare)
Start indoors: Mar 3 Transplant: Apr 14 🍅 Harvest: Jul 14 – Aug 11
Safe Start (90%) ✓ Fits season (80 days to spare)
Start indoors: Mar 22 Transplant: May 3 🍅 Harvest: Aug 2 – Aug 30

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 Jefferson County

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

Soil pH

Your soil pH (5.7–6.8) overlaps with Kabocha's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Kabocha.

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
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 4.3" 0" ❄️ Dormant
Feb 4.2" 0" ❄️ Dormant
Mar 4.3" 4.9" 0" ✅ Rainfall sufficient
Apr 4.3" 3.9" 0.4" 💧 Light watering
May 4.3" 4.1" 0.2" 💧 Light watering
Jun 4.3" 4.2" 0.1" 💧 Light watering
Jul 4.3" 4.2" 0.1" 💧 Light watering
Aug 4.3" 4.4" 0" ✅ Rainfall sufficient
Sep 4.3" 3.2" 1.1" 💧 Light watering
Oct 4.3" 3.3" 1" 💧 Light watering
Nov 3.3" 0" ❄️ Dormant
Dec 3.8" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Oct in Jefferson 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 ~1,896 GDD — county provides 4,387 GDD Excellent fit

Kabocha Planting Timeline — Jefferson County, AL

Kabocha Planting Calendar

Activity When Date Range
Start Indoors March 3 Mar 3 – Mar 17
Transplant Outdoors April 14 Apr 14 – Apr 28
Direct Sow April 7 Apr 7 – Apr 28
Harvest July 14 Jul 14 – Aug 11

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

85–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 8a

📆 Growing Season

214 days in Jefferson County

Growing Tips for Kabocha in Jefferson County

Direct sow Kabocha outdoors after March 31 in Jefferson County when soil has warmed and frost danger has passed.

With Jefferson County's clay soil (34% clay), work in 3-4 inches of compost before planting Kabocha. Avoid tilling when soil is wet to prevent compaction.

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 Jefferson County, AL?

Jefferson County is in Zone 8a with an average last frost of March 31. Plan your Kabocha planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jefferson County, AL?

Jefferson County, Alabama is in USDA Hardiness Zone 8a. The average last spring frost is March 31 and first fall frost is October 31.

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Your Jefferson County Garden Planner — Free

A 24-page printable planner built for Jefferson County (Zone 8a). 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 Jefferson County, AL. 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.