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When to Plant Squash (Summer) in Kendall County, IL

Summer squash includes zucchini, yellow crookneck, and pattypan varieties that are harvested young and tender. They are prolific producers in warm weather.

Kendall County, Illinois is in USDA Zone 5a. The average last spring frost is April 20 and the first fall frost is October 17, giving you a growing season of approximately 180 days.

At an elevation of 708 feet, Kendall County receives approximately 38.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Squash (Summer) during the growing season.

Kendall County, IL (Zone 5a) Moderate season
180 days
Last Spring Frost April 20
180 growing days
First Fall Frost October 17

Kendall County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (56 days to spare)
Start indoors: Mar 10 Transplant: Apr 28 🍅 Harvest: Jun 16 – Aug 18
Recommended (50%) ✓ Fits season (54 days to spare)
Start indoors: Mar 16 Transplant: May 4 🍅 Harvest: Jun 22 – Aug 24
Safe Start (90%) ✓ Fits season (49 days to spare)
Start indoors: Apr 4 Transplant: May 23 🍅 Harvest: Jul 11 – Sep 12

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 Kendall County

How your county's soil matches Squash (Summer)'s growing requirements.

Soil pH

Your soil pH (6.1โ€“6.8) is within Squash (Summer)'s preferred range (6.0โ€“7.5).

Soil Texture

The silt loam soil in Kendall County is excellent for Squash (Summer) โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.9%) โ€” Squash (Summer) will thrive.

How to Plant Squash (Summer)

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

Succession Planting Squash (Summer)

4
successive plantings in your 180-day season

Sow every 5.1 weeks. Last sowing by Aug 13 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 174 gal / 100 sq ft

Monthly Watering Guide for Squash (Summer)

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

Month Squash (Summer) Needs Rainfall You Supplement Action
Jan โ€” 1.7" 0" โ„๏ธ Dormant
Feb โ€” 1.7" 0" โ„๏ธ Dormant
Mar โ€” 3" 0" โ„๏ธ Dormant
Apr 4.3" 3.9" 0.4" ๐Ÿ’ง Light watering
May 4.3" 4.6" 0" โœ… Rainfall sufficient
Jun 4.3" 5.3" 0" โœ… Rainfall sufficient
Jul 4.3" 4.1" 0.2" ๐Ÿ’ง Light watering
Aug 4.3" 3.4" 0.9" ๐Ÿ’ง Light watering
Sep 4.3" 3" 1.3" ๐Ÿ’ง Light watering
Oct 4.3" 2.9" 1.4" ๐Ÿ’ง Light watering
Nov โ€” 2.9" 0" โ„๏ธ Dormant
Dec โ€” 1.8" 0" โ„๏ธ Dormant

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

Squash (Summer) 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.

Squash (Summer) needs ~756 GDD — county provides 2,475 GDD Excellent fit

Squash (Summer) Planting Timeline โ€” Kendall County, IL

Squash (Summer) Planting Calendar

Activity When Date Range
Start Indoors March 16 Mar 16 โ€“ Mar 30
Transplant Outdoors May 4 May 4 โ€“ May 18
Direct Sow April 27 Apr 27 โ€“ May 18
Harvest June 22 Jun 22 โ€“ Aug 24

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

45โ€“65 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 5a

๐Ÿ“† Growing Season

180 days in Kendall County

Growing Tips for Squash (Summer) in Kendall County

Direct sow Squash (Summer) outdoors after April 20 in Kendall County when soil has warmed and frost danger has passed.

Your generous 180.0-day season in Kendall County allows multiple plantings of Squash (Summer). Sow every 22.0 days for continuous harvest.

Common pests for Squash (Summer) 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 frequently when fruits are 6-8 inches for best texture. Check plants daily as they grow rapidly in summer heat.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Squash (Summer) in Kendall County, IL?

Kendall County is in Zone 5a with an average last frost of April 20. Plan your Squash (Summer) planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Kendall County, IL?

Kendall County, Illinois is in USDA Hardiness Zone 5a. The average last spring frost is April 20 and first fall frost is October 17.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Kendall County gardeners in Zone 5a 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 Kendall County, IL. Local conditions may vary. Last updated: April 2026.