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When to plant Kabocha in Marshall County, IA

The best window to plant Kabocha in Marshall County, is May 9–May 30, when soil warms to 50°F. Last frost typically hits May 2; first frost October 7.

When to Plant Kabocha in Marshall 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.

Marshall County, Iowa is in USDA Zone 5a. The average last spring frost is May 2 and the first fall frost is October 7, giving you a growing season of approximately 158 days.

At an elevation of 1,379 feet, Marshall County receives approximately 33.1 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.

Marshall County, IA (Zone 5a) Moderate season
158 days
Last Spring Frost May 2
158 growing days
First Fall Frost October 7

Marshall County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.1

Drainage

Well Drained

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 1.5" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 3" 0" ❄️ Dormant
May 4.3" 3.5" 0.8" 💧 Light watering
Jun 4.3" 4.7" 0" ✅ Rainfall sufficient
Jul 4.3" 4" 0.3" 💧 Light watering
Aug 4.3" 3.5" 0.8" 💧 Light watering
Sep 4.3" 2.9" 1.4" 💧 Light watering
Oct 4.3" 2.3" 2" 💧 Light watering
Nov 2.3" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Marshall County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Kabocha Planting Timeline — Marshall County, IA

Kabocha Planting Calendar

Activity When Date Range
Start Indoors March 28 Mar 28 – Apr 11
Transplant Outdoors May 16 May 16 – May 30
Direct Sow May 9 May 9 – May 30
Harvest August 15 Aug 15 – Sep 12

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
July
August Harvest
September Harvest
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

85–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: N/A

🗺️ USDA Zone

Zone 5a

📆 Growing Season

158 days in Marshall County

Growing Tips for Marshall 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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Kabocha in Marshall County, IA?

Marshall County is in Zone 5a 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 Marshall County, IA?

Marshall County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is May 2 and first fall frost is October 7.

When should I plant Kabocha in Marshall County, IA?

In Marshall County, IA, plant Kabocha after the last frost (around May 2) and before the first frost (around October 7). Best results when soil holds above 50°F.

What growing zone is Marshall County, IA for Kabocha?

Marshall County sits in USDA Zone 5a. Kabocha grows reliably in zones 3a through 11b, so it's a good fit here.

Can Kabocha grow in Marshall County's climate?

Yes — Kabocha grows well in Marshall County's temperate climate. Marshall County averages a 158-day frost-free season, with last frost around May 2 and first frost around October 7.

🌱

Your Marshall County Garden Planner — Free

A 22-page printable planner built for Marshall County (Zone 5a). 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 Marshall County, IA. Local conditions may vary. Last updated: June 2026.

Sources & credits

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