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When to plant Squash (Winter) in Marion County, IA

In Zone 5b (Marion County), direct-sow Squash (Winter) between May 8 and May 29 for spring, after the May 1 last-frost mark.

When to Plant Squash (Winter) in Marion County, IA

Winter squash includes butternut, acorn, delicata, and hubbard varieties grown to full maturity with hard rinds for storage. They develop sweet, dense flesh.

Marion County, Iowa is in USDA Zone 5b. The average last spring frost is May 1 and the first fall frost is October 7, giving you a growing season of approximately 159 days.

At an elevation of 971 feet, Marion County receives approximately 33.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Squash (Winter) to ensure they mature before fall.

Marion County, IA (Zone 5b) Moderate season
159 days
Last Spring Frost May 1
159 growing days
First Fall Frost October 7

Marion County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.2

Drainage

Well Drained

Monthly Watering Guide for Squash (Winter)

Squash (Winter) needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Squash (Winter) Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 3.2" 0" ❄️ Dormant
May 4.3" 4.1" 0.2" 💧 Light watering
Jun 4.3" 4.1" 0.2" 💧 Light watering
Jul 4.3" 3.8" 0.5" 💧 Light watering
Aug 4.3" 3" 1.3" 💧 Light watering
Sep 4.3" 2.8" 1.5" 💧 Light watering
Oct 4.3" 2.7" 1.6" 💧 Light watering
Nov 2.3" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

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

Squash (Winter) Planting Timeline — Marion County, IA

Squash (Winter) Planting Calendar

Activity When Date Range
Start Indoors March 27 Mar 27 – Apr 10
Transplant Outdoors May 15 May 15 – May 29
Direct Sow May 8 May 8 – May 29
Harvest August 7 Aug 7 – Oct 2

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 Harvest
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 5b

📆 Growing Season

159 days in Marion County

Growing Tips for Marion County

Direct sow after last frost on rich mounds. Allow ample space for sprawling vines. Cure harvested fruits in the sun for 10 days before storing 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 Squash (Winter) in Marion County, IA?

Marion County is in Zone 5b with an average last frost of May 1. Plan your Squash (Winter) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Marion County, IA?

Marion County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is May 1 and first fall frost is October 7.

When should I plant Squash (Winter) in Marion County, IA?

In Marion County, IA, plant Squash (Winter) after the last frost (around May 1) and before the first frost (around October 7). Best results when soil holds above 50°F.

What growing zone is Marion County, IA for Squash (Winter)?

Marion County sits in USDA Zone 5b. Squash (Winter) grows reliably in zones 3a through 11b, so it's a good fit here.

Can Squash (Winter) grow in Marion County's climate?

Yes — Squash (Winter) grows well in Marion County's temperate climate. Marion County averages a 159-day frost-free season, with last frost around May 1 and first frost around October 7.

🌱

Your Marion County Garden Planner — Free

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

Sources & credits

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