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When to plant Zucchini in Lee County County,

For Zucchini in Lee County County, the safe spring window opens around April 29 and closes around May 20. Last expected frost is April 22, first fall frost October 14, giving a 175-day growing season.

When to Plant Zucchini in Lee County, IL

Zucchini
Lee County, Illinois Zone 5b June

June in the garden — Lee County, Illinois

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

Avg. last frost April 22
Avg. first frost October 14
Soil temp (4") 69°F
Watering Low
Pest pressure High
Daylight 15 hrs
  1. It's harvest week for zucchini

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

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Zucchini is an incredibly prolific summer squash that can produce an abundance of fruit from just a few plants. It is versatile in the kitchen from grilling to baking.

Lee County, Illinois is in USDA Zone 5b. The average last spring frost is April 22 and the first fall frost is October 14, giving you a growing season of approximately 175 days.

At an elevation of 1,010 feet, Lee County receives approximately 33.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Zucchini to ensure they mature before fall.

Lee County, IL (Zone 5b) Moderate season
175 days
Last Spring Frost April 22
175 growing days
First Fall Frost October 14

Lee County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.9

Drainage

Well Drained

Zucchini Planting Risk Windows

Early Start (70% safe) ✓ Fits season (57 days to spare)
Start indoors: Mar 13 Transplant: May 1 🍅 Harvest: Jun 19 – Aug 14
Recommended (50%) ✓ Fits season (56 days to spare)
Start indoors: Mar 18 Transplant: May 6 🍅 Harvest: Jun 24 – Aug 19
Safe Start (90%) ✓ Fits season (57 days to spare)
Start indoors: Mar 31 Transplant: May 19 🍅 Harvest: Jul 7 – Sep 1

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 Lee County

How your county's soil matches Zucchini's growing requirements.

Soil pH

Your soil pH (6.3–6.9) is within Zucchini's preferred range (6.0–7.5).

Soil Texture

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

Drainage

Drainage is adequate for Zucchini.

Organic Matter

Organic matter is excellent (4.8%) — Zucchini will thrive.

How to Plant Zucchini

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

Succession Planting Zucchini

4
successive plantings in your 175-day season

Sow every 5.1 weeks. Last sowing by Aug 15 to harvest before frost.

Zucchini Water Budget

Plant needs
1.2″/week
Rainfall provides
0.8″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 1,408 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Zucchini

Zucchini needs approximately 1.2 inches of water per week (5.2" per month). Here's how your county's rainfall compares month by month.

Month Zucchini Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 5.2" 2.8" 2.4" 💧 Light watering
May 5.2" 4.4" 0.8" 💧 Light watering
Jun 5.2" 4.2" 1" 💧 Light watering
Jul 5.2" 3.3" 1.9" 💧 Light watering
Aug 5.2" 3.5" 1.7" 💧 Light watering
Sep 5.2" 2.9" 2.3" 💧 Light watering
Oct 5.2" 2.7" 2.5" 💧 Light watering
Nov 2.7" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Lee County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Zucchini 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.

Zucchini needs ~682 GDD — county provides 2,275 GDD Excellent fit

Zucchini Planting Timeline — Lee County, IL

Zucchini Planting Calendar

Activity When Date Range
Start Indoors March 18 Mar 18 – Apr 1
Transplant Outdoors May 6 May 6 – May 20
Direct Sow April 29 Apr 29 – May 20
Harvest June 24 Jun 24 – Aug 19

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

1.2"/week · 2-3 times/week

📅 Days to Maturity

45–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 5b

📆 Growing Season

175 days in Lee County

Growing Tips for Zucchini in Lee County

Direct sow Zucchini outdoors after April 22 in Lee County when soil has warmed and frost danger has passed.

Your generous 175.0-day season in Lee County allows multiple plantings of Zucchini. Sow every 22.0 days for continuous harvest.

Common pests for Zucchini 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. Harvest when fruits are 6-8 inches long for best flavor and texture. Check plants daily in summer as fruits can double in size overnight.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Zucchini in Lee County, IL?

Lee County is in Zone 5b with an average last frost of April 22. Plan your Zucchini planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lee County, IL?

Lee County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 22 and first fall frost is October 14.

When should I plant Zucchini in Lee County, ?

In Lee County, , plant Zucchini after the last frost (around April 22) and before the first frost (around October 14). Best results when soil holds above 50°F.

What growing zone is Lee County, for Zucchini?

Lee County sits in USDA Zone 5b. Zucchini grows reliably in zones 3a through 11b, so it's a good fit here.

Can Zucchini grow in Lee County's climate?

Yes — Zucchini grows well in Lee County's temperate climate. Lee County averages a 175-day frost-free season, with last frost around April 22 and first frost around October 14.

🌱

Your Lee County Garden Planner — Free

A 22-page printable planner built for Lee 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 Lee 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.