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When to Plant Patty Pan Squash in St. Clair County, IL

Patty pan squash is a summer squash with a distinctive flying-saucer shape and scalloped edges. It comes in white, yellow, and green varieties with a mild, nutty flavor.

St. Clair County, Illinois is in USDA Zone 6b. 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 89ยฐF, providing good warmth for Patty Pan Squash during the growing season.

St. Clair County, IL (Zone 6b) 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

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (125 days to spare)
Start indoors: Feb 19 Transplant: Apr 9 🍅 Harvest: May 28 – Jun 25
Recommended (50%) ✓ Fits season (123 days to spare)
Start indoors: Feb 26 Transplant: Apr 16 🍅 Harvest: Jun 4 – Jul 2
Safe Start (90%) ✓ Fits season (129 days to spare)
Start indoors: Mar 13 Transplant: May 1 🍅 Harvest: Jun 19 – Jul 17

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. Clair County

How your county's soil matches Patty Pan Squash's growing requirements.

Soil pH

Your soil pH (6.0โ€“7.3) is within Patty Pan Squash's preferred range (6.0โ€“7.5).

Soil Texture

The silt loam soil in St. Clair County is excellent for Patty Pan Squash โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.1%) โ€” Patty Pan Squash will thrive.

How to Plant Patty Pan Squash

1"
Planting Depth
30"
Between Plants
42"
Between Rows

Succession Planting Patty Pan Squash

5
successive plantings in your 214-day season

Sow every 5.1 weeks. Last sowing by Sep 03 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 756 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Monthly Watering Guide for Patty Pan Squash

Patty Pan 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 Patty Pan Squash Needs Rainfall You Supplement Action
Jan โ€” 1.5" 0" โ„๏ธ Dormant
Feb โ€” 1.5" 0" โ„๏ธ Dormant
Mar โ€” 2.5" 0" โ„๏ธ Dormant
Apr 4.3" 3.2" 1.1" ๐Ÿ’ง Light watering
May 4.3" 3.8" 0.5" ๐Ÿ’ง Light watering
Jun 4.3" 4" 0.3" ๐Ÿ’ง Light watering
Jul 4.3" 3.8" 0.5" ๐Ÿ’ง Light watering
Aug 4.3" 3.9" 0.4" ๐Ÿ’ง Light watering
Sep 4.3" 3.3" 1" ๐Ÿ’ง Light watering
Oct 4.3" 2.5" 1.8" ๐Ÿ’ง Light watering
Nov 4.3" 2.4" 1.9" ๐Ÿ’ง Light watering
Dec โ€” 1.8" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Nov in St. Clair County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Patty Pan Squash 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" โ€” every day above 50ยฐF 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.

Patty Pan Squash needs ~879 GDD — county provides 3,584 GDD Excellent fit

Patty Pan Squash Planting Timeline โ€” St. Clair County, IL

Patty Pan Squash Planting Calendar

Activity When Date Range
Start Indoors February 26 Feb 26 โ€“ Mar 12
Transplant Outdoors April 16 Apr 16 โ€“ Apr 30
Direct Sow April 9 Apr 9 โ€“ Apr 30
Harvest June 4 Jun 4 โ€“ Jul 2

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

45โ€“60 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 6b

๐Ÿ“† Growing Season

214 days in St. Clair County

Growing Tips for Patty Pan Squash in St. Clair County

Direct sow Patty Pan Squash outdoors after April 02 in St. Clair County when soil has warmed and frost danger has passed.

Your generous 214.0-day season in St. Clair County allows multiple plantings of Patty Pan Squash. Sow every 22.0 days for continuous harvest.

Common pests for Patty Pan Squash 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 last frost. Harvest when 2-4 inches across for best texture and flavor. Larger fruits become seedy and tough. Very prolific producers in warm weather.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

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

St. Clair County is in Zone 6b with an average last frost of April 2. Plan your Patty Pan Squash planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is St. Clair County, IL?

St. Clair County, Illinois is in USDA Hardiness Zone 6b. The average last spring frost is April 2 and first fall frost is November 2.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help St. Clair County gardeners in Zone 6b 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 St. Clair County, IL. Local conditions may vary. Last updated: April 2026.