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When to plant Delicata Squash in Williamson County, IL

For Delicata Squash in Williamson County, the safe spring window opens around April 17 and closes around May 8. Last expected frost is April 10, first fall frost October 20, giving a 193-day growing season.

When to Plant Delicata Squash in Williamson County, IL

Williamson County, Illinois Zone 7a June

June in the garden — Williamson County, Illinois

Each item below is timed to Williamson County, Illinois's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 10
Avg. first frost October 20
Soil temp (4") 74°F
Watering Low
Pest pressure High
Daylight 14.6 hrs

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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.

Williamson County, Illinois is in USDA Zone 7a. The average last spring frost is April 10 and the first fall frost is October 20, giving you a growing season of approximately 193 days.

At an elevation of 1,253 feet, Williamson County receives approximately 38.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Delicata Squash during the growing season.

Williamson County, IL (Zone 7a) Moderate season
193 days
Last Spring Frost April 10
193 growing days
First Fall Frost October 20

Williamson County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.2

Drainage

Well Drained

Delicata Squash Planting Risk Windows

Early Start (70% safe) ✓ Fits season (58 days to spare)
Start indoors: Mar 8 Transplant: Apr 19 🍅 Harvest: Jul 12 – Aug 16
Recommended (50%) ✓ Fits season (60 days to spare)
Start indoors: Mar 13 Transplant: Apr 24 🍅 Harvest: Jul 17 – Aug 21
Safe Start (90%) ✓ Fits season (59 days to spare)
Start indoors: Mar 25 Transplant: May 6 🍅 Harvest: Jul 29 – Sep 2

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 Williamson County

How your county's soil matches Delicata Squash's growing requirements.

Soil pH

Your soil pH (6.2–7.2) overlaps with Delicata Squash's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.4%) — Delicata Squash will thrive.

How to Plant Delicata Squash

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

Succession Planting Delicata Squash

2
successive plantings in your 193-day season

Sow every 9.1 weeks. Last sowing by Jul 12 to harvest before frost.

Delicata Squash Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 339 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 1.7" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 4.3" 4" 0.3" 💧 Light watering
May 4.3" 4.9" 0" ✅ Rainfall sufficient
Jun 4.3" 4.8" 0" ✅ Rainfall sufficient
Jul 4.3" 4.3" 0" ✅ Rainfall sufficient
Aug 4.3" 3.7" 0.6" 💧 Light watering
Sep 4.3" 3.2" 1.1" 💧 Light watering
Oct 4.3" 2.9" 1.4" 💧 Light watering
Nov 2.4" 0" ❄️ Dormant
Dec 2.4" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Williamson 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 ~1,642 GDD — county provides 3,522 GDD Excellent fit

Delicata Squash Planting Timeline — Williamson County, IL

Delicata Squash Planting Calendar

Activity When Date Range
Start Indoors March 13 Mar 13 – Mar 27
Transplant Outdoors April 24 Apr 24 – May 8
Direct Sow April 17 Apr 17 – May 8
Harvest July 17 Jul 17 – Aug 21

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

80–100 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

193 days in Williamson County

Growing Tips for Delicata Squash in Williamson County

Direct sow Delicata Squash outdoors after April 10 in Williamson 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 Williamson County, IL?

Williamson County is in Zone 7a with an average last frost of April 10. Plan your Delicata Squash planting based on this frost date — see the calendar above for exact timing.

What planting zone is Williamson County, IL?

Williamson County, Illinois is in USDA Hardiness Zone 7a. The average last spring frost is April 10 and first fall frost is October 20.

When should I plant Delicata Squash in Williamson County, IL?

In Williamson County, IL, plant Delicata Squash after the last frost (around April 10) and before the first frost (around October 20). Best results when soil holds above 50°F.

What growing zone is Williamson County, IL for Delicata Squash?

Williamson 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 Williamson County's climate?

Yes — Delicata Squash grows well in Williamson County's temperate climate. Williamson County averages a 193-day frost-free season, with last frost around April 10 and first frost around October 20.

🌱

Your Williamson County Garden Planner — Free

A 22-page printable planner built for Williamson 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 Williamson 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.