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When to Plant Kabocha in Beltrami County, MN

Beltrami County, Minnesota Zone 3b May

May in Beltrami County, Minnesota — your action list

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

Avg. last frost May 16
Avg. first frost September 28
Soil temp (4") 50°F
Watering Low
Pest pressure Low
Daylight 15 hrs
  1. Plant kabocha from seed, right in the garden

    Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.

June prep starts now
  • Transplants going out: 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.

Beltrami County, Minnesota is in USDA Zone 3b. The average last spring frost is May 16 and the first fall frost is September 28, giving you a growing season of approximately 135 days.

At an elevation of 1,023 feet, Beltrami County receives approximately 39.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 79°F, so choose short-season varieties of Kabocha to ensure they mature before fall.

Beltrami County, MN (Zone 3b) Short season
135 days
Last Spring Frost May 16
135 growing days
First Fall Frost September 28

Beltrami County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 29 Transplant: May 31 🍅 Harvest: Aug 30 – Sep 27
Recommended (50%) ✗ May not fit
Start indoors: Apr 4 Transplant: Jun 6 🍅 Harvest: Sep 5 – Oct 3
Safe Start (90%) ✗ May not fit
Start indoors: Apr 24 Transplant: Jun 26 🍅 Harvest: Sep 25 – Oct 23

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 Beltrami County

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

Soil pH

Your soil pH (5.9–7.0) overlaps with Kabocha's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.4%) — 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
1.2″/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 1.5" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 3.6" 0" ❄️ Dormant
May 4.3" 4.6" 0" ✅ Rainfall sufficient
Jun 4.3" 5.2" 0" ✅ Rainfall sufficient
Jul 4.3" 4.6" 0" ✅ Rainfall sufficient
Aug 4.3" 4.2" 0.1" 💧 Light watering
Sep 4.3" 3.4" 0.9" 💧 Light watering
Oct 3.2" 0" ❄️ Dormant
Nov 2.4" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Beltrami 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 ~856 GDD — county provides 1,248 GDD Excellent fit

Kabocha Planting Timeline — Beltrami County, MN

Kabocha Planting Calendar

Activity When Date Range
Start Indoors April 4 Apr 4 – Apr 18
Transplant Outdoors June 6 Jun 6 – Jun 20
Direct Sow May 30 May 30 – Jun 20
Harvest September 5 Sep 5 – Oct 3

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

Month-by-Month Timeline

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

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 3b

📆 Growing Season

135 days in Beltrami County

Growing Tips for Kabocha in Beltrami County

Direct sow Kabocha outdoors after May 16 in Beltrami 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 Beltrami County, MN?

Beltrami County is in Zone 3b with an average last frost of May 16. Plan your Kabocha planting based on this frost date — see the calendar above for exact timing.

What planting zone is Beltrami County, MN?

Beltrami County, Minnesota is in USDA Hardiness Zone 3b. The average last spring frost is May 16 and first fall frost is September 28.

🌱

Your Beltrami County Garden Planner — Free

A 24-page printable planner built for Beltrami County (Zone 3b). 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 Beltrami County, MN. 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.