When to Plant Kabocha in St. Croix County, WI
This month in St. Croix County, Wisconsin
May is a pivotal month for St. Croix County, Wisconsin gardens. Focus on these tasks first and you'll set up the rest of the season for success.
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Get kabocha in the ground
Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.
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Plant kabocha from seed, right in the garden
Succession planting is the secret here. Put in a row now, another in 2 weeks, a third in 4.
A few tasks this May that'll pay off in June
- 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.
St. Croix County, Wisconsin is in USDA Zone 4b. The average last spring frost is April 28 and the first fall frost is October 9, giving you a growing season of approximately 164 days.
At an elevation of 1,245 feet, St. Croix County receives approximately 38.7 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.
St. Croix County Soil Profile
Soil Type
Silt Loam
Soil pH
6.2-6.7
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 St. Croix County
How your county's soil matches Kabocha's growing requirements.
Soil pH
Your soil pH (6.2–6.7) is within Kabocha's preferred range (6.0–7.5).
Soil Texture
The silt loam soil in St. Croix County is excellent for Kabocha — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.8%) — Kabocha will thrive.
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 | — | 1.8" | 0" | ❄️ Dormant |
| Feb | — | 1.6" | 0" | ❄️ Dormant |
| Mar | — | 2.8" | 0" | ❄️ Dormant |
| Apr | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| May | 4.3" | 4.9" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| Jul | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| Aug | 4.3" | 4.6" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Oct | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| Nov | — | 2.7" | 0" | ❄️ Dormant |
| Dec | — | 2.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in St. Croix 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 — St. Croix County, WI
Kabocha Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 17 | Mar 17 – Mar 31 |
| Transplant Outdoors | May 19 | May 19 – Jun 2 |
| Direct Sow | May 12 | May 12 – Jun 2 |
| Harvest | August 18 | Aug 18 – Sep 15 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | — |
| 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 · Only during dry spells
📅 Days to Maturity
85–100 days
🧪 Soil pH
Needs 6–7.5 · Your soil: ideal
🗺️ USDA Zone
Zone 4b
📆 Growing Season
164 days in St. Croix County
Growing Tips for Kabocha in St. Croix County
Direct sow Kabocha outdoors after April 28 in St. Croix 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 St. Croix County, WI?
St. Croix County is in Zone 4b with an average last frost of April 28. Plan your Kabocha planting based on this frost date — see the calendar above for exact timing.
What planting zone is St. Croix County, WI?
St. Croix County, Wisconsin is in USDA Hardiness Zone 4b. The average last spring frost is April 28 and first fall frost is October 9.
Your St. Croix County Garden Planner — Free
A 24-page printable planner built for St. Croix 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.