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When to Plant Zucchini in Scott County, IL

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.

Scott County, Illinois is in USDA Zone 5b. The average last spring frost is April 14 and the first fall frost is October 17, giving you a growing season of approximately 186 days.

At an elevation of 987 feet, Scott County receives approximately 37.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Zucchini to ensure they mature before fall.

Scott County, IL (Zone 5b) Moderate season
186 days
Last Spring Frost April 14
186 growing days
First Fall Frost October 17

Scott County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (66 days to spare)
Start indoors: Mar 5 Transplant: Apr 23 🍅 Harvest: Jun 11 – Aug 6
Recommended (50%) ✓ Fits season (67 days to spare)
Start indoors: Mar 10 Transplant: Apr 28 🍅 Harvest: Jun 16 – Aug 11
Safe Start (90%) ✓ Fits season (61 days to spare)
Start indoors: Mar 27 Transplant: May 15 🍅 Harvest: Jul 3 – Aug 28

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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 750 gal / 100 sq ft
Zucchini needs ~682 GDD — county provides 2,418 GDD Excellent fit

Zucchini Planting Timeline โ€” Scott County, IL

Zucchini Planting Calendar

Activity When Date Range
Start Indoors March 10 Mar 10 โ€“ Mar 24
Transplant Outdoors April 28 Apr 28 โ€“ May 12
Direct Sow April 21 Apr 21 โ€“ May 12
Harvest June 16 Jun 16 โ€“ Aug 11

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

45โ€“60 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 5b

Growing Season

186 days

Growing Tips for Scott County

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

Level Up Your Garden

Frequently Asked Questions

When should I plant Zucchini in Scott County, IL?

Scott County is in Zone 5b with an average last frost of April 14. Plan your Zucchini planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Scott County, IL?

Scott County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 14 and first fall frost is October 17.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Scott County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.

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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 Scott County, IL. Local conditions may vary. Last updated: April 2026.