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When to plant Butternut Squash in St. Clair County, IL

Plant Butternut Squash in St. Clair County from April 9 to April 30 in spring. St. Clair County sits in USDA Zone 7a, with last frost around April 2 and first frost on November 2.

When to Plant Butternut Squash in St. Clair County, IL

Butternut squash is a popular winter squash with a long neck, small seed cavity, and sweet, nutty orange flesh. It stores exceptionally well for months.

St. Clair County, Illinois is in USDA Zone 7a. The average last spring frost is April 2 and the first fall frost is November 2, giving you a growing season of approximately 214 days.

At an elevation of 711 feet, St. Clair County receives approximately 34.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Butternut Squash during the growing season.

St. Clair County, IL (Zone 7a) Long season
214 days
Last Spring Frost April 2
214 growing days
First Fall Frost November 2

St. Clair County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.3

Drainage

Well Drained

Monthly Watering Guide for Butternut Squash

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

Month Butternut Squash Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 4.3" 3.2" 1.1" 💧 Light watering
May 4.3" 3.8" 0.5" 💧 Light watering
Jun 4.3" 4" 0.3" 💧 Light watering
Jul 4.3" 3.8" 0.5" 💧 Light watering
Aug 4.3" 3.9" 0.4" 💧 Light watering
Sep 4.3" 3.3" 1" 💧 Light watering
Oct 4.3" 2.5" 1.8" 💧 Light watering
Nov 4.3" 2.4" 1.9" 💧 Light watering
Dec 1.8" 0" ❄️ Dormant

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

Butternut Squash Planting Timeline — St. Clair County, IL

Butternut Squash Planting Calendar

Activity When Date Range
Start Indoors March 5 Mar 5 – Mar 19
Transplant Outdoors April 16 Apr 16 – Apr 30
Direct Sow April 9 Apr 9 – Apr 30
Harvest July 16 Jul 16 – Aug 20

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

85–110 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 7a

📆 Growing Season

214 days in St. Clair County

Growing Tips for St. Clair County

Start seeds indoors 3 weeks early or direct sow after frost. Allow 6-8 feet for sprawling vines. Harvest when the skin is hard and uniformly tan. Cure in the sun for 10 days.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Butternut Squash in St. Clair County, IL?

St. Clair County is in Zone 7a with an average last frost of April 2. Plan your Butternut Squash planting based on this frost date — see the calendar above for exact timing.

What planting zone is St. Clair County, IL?

St. Clair County, Illinois is in USDA Hardiness Zone 7a. The average last spring frost is April 2 and first fall frost is November 2.

When should I plant Butternut Squash in St. Clair County, IL?

In St. Clair County, IL, plant Butternut Squash after the last frost (around April 2) and before the first frost (around November 2). Best results when soil holds above 50°F.

What growing zone is St. Clair County, IL for Butternut Squash?

St. Clair County sits in USDA Zone 7a. Butternut Squash grows reliably in zones 3a through 11b, so it's a good fit here.

Can Butternut Squash grow in St. Clair County's climate?

Yes — Butternut Squash grows well in St. Clair County's temperate climate. St. Clair County averages a 214-day frost-free season, with last frost around April 2 and first frost around November 2.

🌱

Your St. Clair County Garden Planner — Free

A 22-page printable planner built for St. Clair County (Zone 7a). 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 St. Clair County, IL. Local conditions may vary. Last updated: July 2026.

Sources & credits

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