When to Plant Kabocha in Ontonagon County, MI
Ontonagon County, Michigan gardeners: here's your May plan
A quick May briefing for Ontonagon County, Michigan gardeners — what's urgent, what's next, and what can wait.
June prep starts now
- Transplants going out: kabocha
- Direct-sowing: kabocha
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.
Ontonagon County, Michigan is in USDA Zone 4b. The average last spring frost is May 22 and the first fall frost is September 28, giving you a growing season of approximately 129 days.
At an elevation of 502 feet, Ontonagon County receives approximately 42 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Kabocha to ensure they mature before fall.
Ontonagon County Soil Profile
Soil Type
Silt Loam
Soil pH
6.2-7.2
Drainage
Well Drained
Plant Planting Risk Windows
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 Ontonagon County
How your county's soil matches Kabocha's growing requirements.
Soil pH
Your soil pH (6.2–7.2) is within Kabocha's preferred range (6.0–7.5).
Soil Texture
The silt loam soil in Ontonagon County is excellent for Kabocha — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.1%) — Kabocha will thrive.
How to Plant Kabocha
Plant Water Budget
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 | — | 2" | 0" | ❄️ Dormant |
| Feb | — | 2.1" | 0" | ❄️ Dormant |
| Mar | — | 2.8" | 0" | ❄️ Dormant |
| Apr | — | 4.4" | 0" | ❄️ Dormant |
| May | 4.3" | 4.8" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 5.2" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 4.3" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| Sep | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Oct | — | 3.6" | 0" | ❄️ Dormant |
| Nov | — | 2.6" | 0" | ❄️ Dormant |
| Dec | — | 2.4" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Ontonagon 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 Planting Timeline — Ontonagon County, MI
Kabocha Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 10 | Apr 10 – Apr 24 |
| Transplant Outdoors | June 12 | Jun 12 – Jun 26 |
| Direct Sow | June 5 | Jun 5 – Jun 26 |
| Harvest | September 11 | Sep 11 – Oct 9 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | — |
| 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: ideal
🗺️ USDA Zone
Zone 4b
📆 Growing Season
129 days in Ontonagon County
Growing Tips for Kabocha in Ontonagon County
Direct sow Kabocha outdoors after May 22 in Ontonagon 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
Check more plant combinations with our Companion Planting Checker →
Kabocha in Other Locations
Frequently Asked Questions
When should I plant Kabocha in Ontonagon County, MI?
Ontonagon County is in Zone 4b with an average last frost of May 22. Plan your Kabocha planting based on this frost date — see the calendar above for exact timing.
What planting zone is Ontonagon County, MI?
Ontonagon County, Michigan is in USDA Hardiness Zone 4b. The average last spring frost is May 22 and first fall frost is September 28.
Your Ontonagon County Garden Planner — Free
A 24-page printable planner built for Ontonagon 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.