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When to plant Squash (Summer) in Capron, IL

The best window to plant Squash (Summer) in Capron, is April 30–May 21, when soil warms to 50°F. Last frost typically hits April 23; first frost October 16.

When to Plant Squash (Summer) in Capron, IL

Boone County, Illinois Zone 5b July

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Avg. last frost April 23
Avg. first frost October 16
Soil temp (4") 78°F
Watering Low
Pest pressure High
Daylight 14.8 hrs

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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.

Capron, Illinois is in USDA Zone 5b. The average last spring frost is April 23 and the first fall frost is October 16, giving you a growing season of approximately 176 days.

At an elevation of 512 feet, Boone County receives approximately 39.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Squash (Summer) to ensure they mature before fall.

Capron, IL (Zone 5b) Moderate season
176 days
Last Spring Frost April 23
176 growing days
First Fall Frost October 16

Capron Soil Profile

Soil Type

Silt Loam

Soil pH

6-6.8

Drainage

Well Drained

Squash (Summer) Planting Risk Windows

Early Start (70% safe) ✓ Fits season (51 days to spare)
Start indoors: Mar 13 Transplant: May 1 🍅 Harvest: Jun 19 – Aug 21
Recommended (50%) ✓ Fits season (50 days to spare)
Start indoors: Mar 19 Transplant: May 7 🍅 Harvest: Jun 25 – Aug 27
Safe Start (90%) ✓ Fits season (47 days to spare)
Start indoors: Apr 5 Transplant: May 24 🍅 Harvest: Jul 12 – Sep 13

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 Capron

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

Soil pH

Your soil pH (6.0–6.8) is within Squash (Summer)'s preferred range (6.0–7.5).

Soil Texture

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

Drainage

Drainage is adequate for Squash (Summer).

Organic Matter

Organic matter is moderate (3.8%). Annual compost additions will help Squash (Summer).

How to Plant Squash (Summer)

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

Succession Planting Squash (Summer)

4
successive plantings in your 176-day season

Sow every 5.1 weeks. Last sowing by Aug 12 to harvest before frost.

Squash (Summer) Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 654 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 1.6" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 4.3" 3.4" 0.9" 💧 Light watering
May 4.3" 4.1" 0.2" 💧 Light watering
Jun 4.3" 5.7" 0" ✅ Rainfall sufficient
Jul 4.3" 4.9" 0" ✅ Rainfall sufficient
Aug 4.3" 3.8" 0.5" 💧 Light watering
Sep 4.3" 3.5" 0.8" 💧 Light watering
Oct 4.3" 3.5" 0.8" 💧 Light watering
Nov 2.9" 0" ❄️ Dormant
Dec 2.3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Boone 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 ~674 GDD — county provides 2,156 GDD Excellent fit

Squash (Summer) Planting Timeline — Capron, 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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

45–65 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 5b

📆 Growing Season

176 days in Boone County

Growing Tips for Squash (Summer) in Capron

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

Your generous 176.0-day season in Boone 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 →

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

In Capron, IL, plant Squash (Summer) after the last frost (around April 23) and before the first frost (around October 16). Best results when soil holds above 50°F.

What growing zone is Capron, IL for Squash (Summer)?

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

Can Squash (Summer) grow in Capron's climate?

Yes — Squash (Summer) grows well in Capron's temperate climate. Capron averages a 176-day frost-free season, with last frost around April 23 and first frost around October 16.

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A 22-page printable planner built for Boone County (Zone 5b). 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 Boone County, IL. Local conditions may vary. Last updated: July 2026.