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

St. Clair County, Illinois Zone 7a May

May to-do list for St. Clair County, Illinois

A quick May briefing for St. Clair County, Illinois gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 2
Avg. first frost November 2
Soil temp (4") 63°F
Watering Low
Pest pressure Low
Daylight 14.1 hrs
Looking ahead to June
  • First harvests: crookneck squash

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Yellow crookneck squash is a summer squash with a curved neck and bumpy, bright yellow skin. It has a buttery flavor and is best harvested young when 4-6 inches long.

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 Crookneck 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
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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 26 Transplant: Apr 9 🍅 Harvest: May 28 – Jun 25
Recommended (50%) ✓ Fits season (123 days to spare)
Start indoors: Mar 5 Transplant: Apr 16 🍅 Harvest: Jun 4 – Jul 2
Safe Start (90%) ✓ Fits season (129 days to spare)
Start indoors: Mar 20 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 Crookneck Squash's growing requirements.

Soil pH

Your soil pH (6.0–7.3) is within Crookneck Squash's preferred range (6.0–7.5).

Soil Texture

The silt loam soil in St. Clair County is excellent for Crookneck Squash — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.1%) — Crookneck Squash will thrive.

How to Plant Crookneck Squash

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

Succession Planting Crookneck 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 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Crookneck Squash

Crookneck 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 Crookneck 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.

Crookneck 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" — every day above 50°F 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.

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

Crookneck Squash Planting Timeline — St. Clair County, IL

Crookneck 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 June 4 Jun 4 – Jul 2

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 Harvest
July Harvest
August
September
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

45–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 7a

📆 Growing Season

214 days in St. Clair County

Growing Tips for Crookneck Squash in St. Clair County

Direct sow Crookneck 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 Crookneck Squash. Sow every 22.0 days for continuous harvest.

Common pests for Crookneck 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 on mounds. Pick frequently while small for tender texture. Skin becomes tough and warty on larger fruits. Very productive 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 Crookneck Squash in St. Clair County, IL?

St. Clair County is in Zone 7a with an average last frost of April 2. Plan your Crookneck 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.

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Your St. Clair County Garden Planner — Free

A 24-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: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.