Blog

When to Plant Kabocha in Monroe County, IA

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.

Monroe County, Iowa is in USDA Zone 5a. The average last spring frost is April 26 and the first fall frost is October 13, giving you a growing season of approximately 170 days.

At an elevation of 968 feet, Monroe County receives approximately 32.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87ยฐF, providing good warmth for Kabocha during the growing season.

Monroe County, IA (Zone 5a) Moderate season
170 days
Last Spring Frost April 26
170 growing days
First Fall Frost October 13

Monroe County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (38 days to spare)
Start indoors: Mar 14 Transplant: May 2 🍅 Harvest: Aug 1 – Aug 29
Recommended (50%) ✓ Fits season (37 days to spare)
Start indoors: Mar 22 Transplant: May 10 🍅 Harvest: Aug 9 – Sep 6
Safe Start (90%) ✓ Fits season (35 days to spare)
Start indoors: Apr 8 Transplant: May 27 🍅 Harvest: Aug 26 – Sep 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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 298 gal / 100 sq ft
Kabocha needs ~1,411 GDD — county provides 2,592 GDD Excellent fit

Kabocha Planting Timeline โ€” Monroe County, IA

Kabocha Planting Calendar

Activity When Date Range
Start Indoors March 22 Mar 22 โ€“ Apr 5
Transplant Outdoors May 10 May 10 โ€“ May 24
Direct Sow May 3 May 3 โ€“ May 24
Harvest August 9 Aug 9 โ€“ Sep 6

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

85โ€“100 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 5a

Growing Season

170 days

Growing Tips for Monroe County

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

Level Up Your Garden

Frequently Asked Questions

When should I plant Kabocha in Monroe County, IA?

Monroe County is in Zone 5a with an average last frost of April 26. Plan your Kabocha planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Monroe County, IA?

Monroe County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 26 and first fall frost is October 13.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Monroe County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Monroe County, IA. Local conditions may vary. Last updated: April 2026.