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When to plant Delicata Squash in St. Clair County County,

Aim to plant Delicata Squash in St. Clair County County on or after April 9; the window stays open through April 30. St. Clair County County's 214-day frost-free season gives you enough for a full main crop and a short fall succession.

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

St. Clair County, Illinois Zone 7a June

Your June game plan for St. Clair County, Illinois

If you only do a handful of things in the garden this June, make it these. They're sequenced around your zone's frost timing.

Avg. last frost April 2
Avg. first frost November 2
Soil temp (4") 73°F
Watering Low
Pest pressure High
Daylight 14.7 hrs
Looking ahead to July
  • First harvests: delicata squash

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Delicata squash is a winter squash with an edible skin and sweet, creamy orange flesh. Its compact vines make it suitable for smaller gardens.

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 Delicata 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

Delicata Squash Planting Risk Windows

Early Start (70% safe) ✓ Fits season (83 days to spare)
Start indoors: Feb 26 Transplant: Apr 9 🍅 Harvest: Jul 2 – Aug 6
Recommended (50%) ✓ Fits season (81 days to spare)
Start indoors: Mar 5 Transplant: Apr 16 🍅 Harvest: Jul 9 – Aug 13
Safe Start (90%) ✓ Fits season (87 days to spare)
Start indoors: Mar 20 Transplant: May 1 🍅 Harvest: Jul 24 – Aug 28

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 Delicata Squash's growing requirements.

Soil pH

Your soil pH (6.0–7.3) overlaps with Delicata Squash's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

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

How to Plant Delicata Squash

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

Succession Planting Delicata Squash

3
successive plantings in your 214-day season

Sow every 9.1 weeks. Last sowing by Jul 25 to harvest before frost.

Delicata Squash 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 Delicata Squash

Delicata 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 Delicata 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.

Delicata 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.

Delicata Squash needs ~1,508 GDD — county provides 3,584 GDD Excellent fit

Delicata Squash Planting Timeline — St. Clair County, IL

Delicata 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 9 Jul 9 – Aug 13

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
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

80–100 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

214 days in St. Clair County

Growing Tips for Delicata Squash in St. Clair County

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

Common pests for Delicata 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. Harvest when skin is hard and ivory with green stripes. The thin skin does not need peeling. Stores 2-3 months in a cool 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 Delicata Squash in St. Clair County, IL?

St. Clair County is in Zone 7a with an average last frost of April 2. Plan your Delicata 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 Delicata Squash in St. Clair County, ?

In St. Clair County, , plant Delicata 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, for Delicata Squash?

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

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

Yes — Delicata 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: June 2026.

Sources & credits

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