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When to Plant Zucchini in Union County, IN

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.

Union County, Indiana is in USDA Zone 6a. The average last spring frost is April 25 and the first fall frost is October 17, giving you a growing season of approximately 175 days.

At an elevation of 506 feet, Union County receives approximately 33.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90ยฐF, providing good warmth for Zucchini during the growing season.

Union County, IN (Zone 6a) Moderate season
175 days
Last Spring Frost April 25
175 growing days
First Fall Frost October 17

Union County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (58 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 21 Transplant: May 9 🍅 Harvest: Jun 27 – Aug 22
Safe Start (90%) ✓ Fits season (52 days to spare)
Start indoors: Apr 4 Transplant: May 23 🍅 Harvest: Jul 11 – Sep 5

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
1.2″/week
Rainfall provides
0.8″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 1,177 gal / 100 sq ft
Zucchini needs ~919 GDD — county provides 3,062 GDD Excellent fit

Zucchini Planting Timeline โ€” Union County, IN

Zucchini Planting Calendar

Activity When Date Range
Start Indoors March 21 Mar 21 โ€“ Apr 4
Transplant Outdoors May 9 May 9 โ€“ May 23
Direct Sow May 2 May 2 โ€“ May 23
Harvest June 27 Jun 27 โ€“ Aug 22

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April Start Indoors
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 6a

Growing Season

175 days

Growing Tips for Union 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 Union County, IN?

Union County is in Zone 6a with an average last frost of April 25. Plan your Zucchini planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Union County, IN?

Union County, Indiana is in USDA Hardiness Zone 6a. The average last spring frost is April 25 and first fall frost is October 17.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Union County gardeners in Zone 6a 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 Union County, IN. Local conditions may vary. Last updated: April 2026.