When to Plant Kabocha in Portage County, WI
Top priorities for Portage County, Wisconsin gardeners in May
A quick May briefing for Portage County, Wisconsin gardeners — what's urgent, what's next, and what can wait.
-
Move kabocha into the garden
Your last frost (May 5) has passed. These warm-season crops can handle outdoor soil now.
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Plant kabocha from seed, right in the garden
Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.
Coming up in June — start thinking about
- Starting indoors: 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.
Portage County, Wisconsin is in USDA Zone 4b. The average last spring frost is May 5 and the first fall frost is October 6, giving you a growing season of approximately 154 days.
At an elevation of 1,008 feet, Portage County receives approximately 37.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Kabocha to ensure they mature before fall.
Portage County Soil Profile
Soil Type
Silt Loam
Soil pH
5.9-7.1
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 Portage County
How your county's soil matches Kabocha's growing requirements.
Soil pH
Your soil pH (5.9–7.1) overlaps with Kabocha's range (6.0–7.5), though not a perfect match.
Soil Texture
The silt loam soil in Portage 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 (4.0%). Annual compost additions will help Kabocha.
How to Plant Kabocha
Plant Water Budget
Water stress score is 6/10 — 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 | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.6" | 0" | ❄️ Dormant |
| Mar | — | 2.5" | 0" | ❄️ Dormant |
| Apr | — | 3.1" | 0" | ❄️ Dormant |
| May | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Jun | 4.3" | 4.9" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 4" | 0.3" | 💧 Light watering |
| Aug | 4.3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Oct | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| Nov | — | 2.7" | 0" | ❄️ Dormant |
| Dec | — | 2.4" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Portage 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 — Portage County, WI
Kabocha Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 24 | Mar 24 – Apr 7 |
| Transplant Outdoors | May 26 | May 26 – Jun 9 |
| Direct Sow | May 19 | May 19 – Jun 9 |
| Harvest | August 25 | Aug 25 – Sep 22 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| 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: acceptable
🗺️ USDA Zone
Zone 4b
📆 Growing Season
154 days in Portage County
Growing Tips for Kabocha in Portage County
Direct sow Kabocha outdoors after May 05 in Portage 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 Portage County, WI?
Portage County is in Zone 4b with an average last frost of May 5. Plan your Kabocha planting based on this frost date — see the calendar above for exact timing.
What planting zone is Portage County, WI?
Portage County, Wisconsin is in USDA Hardiness Zone 4b. The average last spring frost is May 5 and first fall frost is October 6.
Your Portage County Garden Planner — Free
A 24-page printable planner built for Portage 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.