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When to Plant Kabocha in Billings County, ND

Billings County, North Dakota Zone 4a May

Your May game plan for Billings County, North Dakota

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Billings County, North Dakota.

Avg. last frost May 19
Avg. first frost September 21
Soil temp (4") 55°F
Watering Moderate
Pest pressure Low
Daylight 14.9 hrs
June will be here before you know it — start on
  • Transplants going out: kabocha
  • Direct-sowing: kabocha
  • Starting indoors: kabocha

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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.

Billings County, North Dakota is in USDA Zone 4a. The average last spring frost is May 19 and the first fall frost is September 21, giving you a growing season of approximately 125 days.

At an elevation of 894 feet, Billings County receives approximately 26.2 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Kabocha to ensure they mature before fall.

Billings County, ND (Zone 4a) Short season
125 days
Last Spring Frost May 19
125 growing days
First Fall Frost September 21
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Billings County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 2 Transplant: Jun 4 🍅 Harvest: Sep 3 – Oct 1
Recommended (50%) ✗ May not fit
Start indoors: Apr 7 Transplant: Jun 9 🍅 Harvest: Sep 8 – Oct 6
Safe Start (90%) ✗ May not fit
Start indoors: Apr 21 Transplant: Jun 23 🍅 Harvest: Sep 22 – Oct 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 Billings County

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

Soil pH

Your soil pH (6.5–7.4) is within Kabocha's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (4.0%). 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
0.1″/week
Watering frequency Only during dry spells
Season total 160 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 1.8" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 3" 0" ❄️ Dormant
May 4.3" 3.3" 1" 💧 Light watering
Jun 4.3" 1.6" 2.7" 🚿 Regular watering
Jul 4.3" 2.3" 2" 💧 Light watering
Aug 4.3" 2.9" 1.4" 💧 Light watering
Sep 4.3" 2.4" 1.9" 💧 Light watering
Oct 2" 0" ❄️ Dormant
Nov 1.7" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Billings 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 ~1,202 GDD — county provides 1,625 GDD Excellent fit

Kabocha Planting Timeline — Billings County, ND

Kabocha Planting Calendar

Activity When Date Range
Start Indoors April 7 Apr 7 – Apr 21
Transplant Outdoors June 9 Jun 9 – Jun 23
Direct Sow June 2 Jun 2 – Jun 23
Harvest September 8 Sep 8 – Oct 6

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May
June Transplant Outdoors Direct Sow
July
August
September Harvest
October Harvest
November
December
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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 4a

📆 Growing Season

125 days in Billings County

Growing Tips for Kabocha in Billings County

Direct sow Kabocha outdoors after May 19 in Billings 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 Billings County, ND?

Billings County is in Zone 4a with an average last frost of May 19. Plan your Kabocha planting based on this frost date — see the calendar above for exact timing.

What planting zone is Billings County, ND?

Billings County, North Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 19 and first fall frost is September 21.

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Your Billings County Garden Planner — Free

A 24-page printable planner built for Billings County (Zone 4a). 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 Billings County, ND. 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.