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When to Plant Kabocha in Swift County, MN

Swift County, Minnesota Zone 4b May

Your May game plan for Swift County, Minnesota

We've pulled the most time-sensitive tasks for Swift County, Minnesota this May and put them front and centre. Tackle them in order.

Avg. last frost May 2
Avg. first frost October 4
Soil temp (4") 56°F
Watering Low
Pest pressure Low
Daylight 14.7 hrs
  1. Move kabocha from tray to bed

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

  2. Sow kabocha where they'll grow

    Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.

June will be here before you know it — start on
  • 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.

Swift County, Minnesota is in USDA Zone 4b. The average last spring frost is May 2 and the first fall frost is October 4, giving you a growing season of approximately 155 days.

At an elevation of 1,212 feet, Swift County receives approximately 35.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Kabocha to ensure they mature before fall.

Swift County, MN (Zone 4b) Moderate season
155 days
Last Spring Frost May 2
155 growing days
First Fall Frost October 4

Swift County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (14 days to spare)
Start indoors: Mar 16 Transplant: May 18 🍅 Harvest: Aug 17 – Sep 14
Recommended (50%) ✓ Fits season (15 days to spare)
Start indoors: Mar 21 Transplant: May 23 🍅 Harvest: Aug 22 – Sep 19
Safe Start (90%) ✓ Fits season (12 days to spare)
Start indoors: Apr 3 Transplant: Jun 5 🍅 Harvest: Sep 4 – Oct 2

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 Swift County

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

Soil pH

Your soil pH (6.3–6.7) is within Kabocha's preferred range (6.0–7.5).

Soil Texture

The silt loam soil in Swift 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 (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
1.0″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 474 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 1.6" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 2.9" 0" ❄️ Dormant
May 4.3" 4.6" 0" ✅ Rainfall sufficient
Jun 4.3" 4.5" 0" ✅ Rainfall sufficient
Jul 4.3" 3.8" 0.5" 💧 Light watering
Aug 4.3" 3.6" 0.7" 💧 Light watering
Sep 4.3" 2.8" 1.5" 💧 Light watering
Oct 4.3" 2.3" 2" 💧 Light watering
Nov 2.6" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Swift 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 ~1,133 GDD — county provides 1,898 GDD Excellent fit

Kabocha Planting Timeline — Swift County, MN

Kabocha Planting Calendar

Activity When Date Range
Start Indoors March 21 Mar 21 – Apr 4
Transplant Outdoors May 23 May 23 – Jun 6
Direct Sow May 16 May 16 – Jun 6
Harvest August 22 Aug 22 – Sep 19

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

85–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 4b

📆 Growing Season

155 days in Swift County

Growing Tips for Kabocha in Swift County

Direct sow Kabocha outdoors after May 02 in Swift 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 Swift County, MN?

Swift County is in Zone 4b with an average last frost of May 2. Plan your Kabocha planting based on this frost date — see the calendar above for exact timing.

What planting zone is Swift County, MN?

Swift County, Minnesota is in USDA Hardiness Zone 4b. The average last spring frost is May 2 and first fall frost is October 4.

🌱

Your Swift County Garden Planner — Free

A 24-page printable planner built for Swift County (Zone 4b). 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 Swift 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.