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When to plant Squash (Summer) in Stephenson County County,

In Stephenson County County, plant Squash (Summer) in spring between April 30 and May 21, once soil temps hold above 50°F. Stephenson County County's last frost averages April 23, so time plantings around the expected last-frost window for best survival. For a fall crop, sow between and — roughly 65 days before the first frost on October 13.

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

Stephenson County, Illinois Zone 5a June

Your June planting checklist for Stephenson County, Illinois

Here's what deserves your attention in Stephenson County, Illinois this month. Everything below is tailored to Zone 5a and timed around your local frost dates.

Avg. last frost April 23
Avg. first frost October 13
Soil temp (4") 66°F
Watering Low
Pest pressure High
Daylight 15.1 hrs
  1. Harvest squash (summer) as they ripen

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

July prep starts now
  • First harvests: squash (summer)

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

Stephenson County, Illinois is in USDA Zone 5a. The average last spring frost is April 23 and the first fall frost is October 13, giving you a growing season of approximately 173 days.

At an elevation of 1,345 feet, Stephenson County receives approximately 36.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Squash (Summer) during the growing season.

Stephenson County, IL (Zone 5a) Moderate season
173 days
Last Spring Frost April 23
173 growing days
First Fall Frost October 13
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Stephenson County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.1

Drainage

Well Drained

Squash (Summer) Planting Risk Windows

Early Start (70% safe) ✓ Fits season (48 days to spare)
Start indoors: Mar 14 Transplant: May 2 🍅 Harvest: Jun 20 – Aug 22
Recommended (50%) ✓ Fits season (47 days to spare)
Start indoors: Mar 19 Transplant: May 7 🍅 Harvest: Jun 25 – Aug 27
Safe Start (90%) ✓ Fits season (45 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 Stephenson County

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

Soil pH

Your soil pH (6.2–7.1) is within Squash (Summer)'s preferred range (6.0–7.5).

Soil Texture

The silt loam soil in Stephenson County is excellent for Squash (Summer) — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.5%) — 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 173-day season

Sow every 5.1 weeks. Last sowing by Aug 09 to harvest before frost.

Squash (Summer) Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 224 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.7" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 4.3" 3.3" 1" 💧 Light watering
May 4.3" 4.7" 0" ✅ Rainfall sufficient
Jun 4.3" 4" 0.3" 💧 Light watering
Jul 4.3" 4.1" 0.2" 💧 Light watering
Aug 4.3" 3.9" 0.4" 💧 Light watering
Sep 4.3" 3.5" 0.8" 💧 Light watering
Oct 4.3" 2.4" 1.9" 💧 Light watering
Nov 2.3" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Stephenson County). Supplement amounts are based on average rainfall — 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" — 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.

Squash (Summer) needs ~756 GDD — county provides 2,378 GDD Excellent fit

Squash (Summer) Planting Timeline — Stephenson County, IL

Squash (Summer) Planting Calendar

Activity When Date Range
Start Indoors March 19 Mar 19 – Apr 2
Transplant Outdoors May 7 May 7 – May 21
Direct Sow April 30 Apr 30 – May 21
Harvest June 25 Jun 25 – Aug 27

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

45–65 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 5a

📆 Growing Season

173 days in Stephenson County

Growing Tips for Squash (Summer) in Stephenson County

Direct sow Squash (Summer) outdoors after April 23 in Stephenson County when soil has warmed and frost danger has passed.

Your generous 173.0-day season in Stephenson 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 Stephenson County, IL?

Stephenson County is in Zone 5a with an average last frost of April 23. Plan your Squash (Summer) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Stephenson County, IL?

Stephenson County, Illinois is in USDA Hardiness Zone 5a. The average last spring frost is April 23 and first fall frost is October 13.

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

In Stephenson County County, , plant Squash (Summer) after the last frost (around April 23) and before the first frost (around October 13). Best results when soil holds above 50°F.

What growing zone is Stephenson County County, for Squash (Summer)?

Stephenson County County sits in USDA Zone 5a. Squash (Summer) grows reliably in zones 3a through 11b, so it's a good fit here.

Can Squash (Summer) grow in Stephenson County County's climate?

Yes — Squash (Summer) grows well in Stephenson County County's temperate climate. Stephenson County County averages a 173-day frost-free season, with last frost around April 23 and first frost around October 13.

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Your Stephenson County Garden Planner — Free

A 22-page printable planner built for Stephenson County (Zone 5a). 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 Stephenson 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.