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When to Plant Zucchini in Franklin 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.

Franklin County, Illinois is in USDA Zone 6b. The average last spring frost is April 10 and the first fall frost is October 20, giving you a growing season of approximately 193 days.

At an elevation of 747 feet, Franklin County receives approximately 37.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89ยฐF, providing good warmth for Zucchini during the growing season.

Franklin County, IL (Zone 6b) Moderate season
193 days
Last Spring Frost April 10
193 growing days
First Fall Frost October 20

Franklin County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (71 days to spare)
Start indoors: Mar 2 Transplant: Apr 20 🍅 Harvest: Jun 8 – Aug 3
Recommended (50%) ✓ Fits season (74 days to spare)
Start indoors: Mar 6 Transplant: Apr 24 🍅 Harvest: Jun 12 – Aug 7
Safe Start (90%) ✓ Fits season (74 days to spare)
Start indoors: Mar 19 Transplant: May 7 🍅 Harvest: Jun 25 – Aug 20

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
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 388 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Zucchini needs ~879 GDD — county provides 3,232 GDD Excellent fit

Zucchini Planting Timeline โ€” Franklin County, IL

Zucchini Planting Calendar

Activity When Date Range
Start Indoors March 6 Mar 6 โ€“ Mar 20
Transplant Outdoors April 24 Apr 24 โ€“ May 8
Direct Sow April 17 Apr 17 โ€“ May 8
Harvest June 12 Jun 12 โ€“ Aug 7

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 6b

Growing Season

193 days

Growing Tips for Franklin 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 Franklin County, IL?

Franklin County is in Zone 6b with an average last frost of April 10. Plan your Zucchini planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Franklin County, IL?

Franklin County, Illinois is in USDA Hardiness Zone 6b. The average last spring frost is April 10 and first fall frost is October 20.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Franklin County gardeners in Zone 6b organize planting dates, track what's growing, and never miss a planting window.

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