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When to Plant Sunflower in Rush County, IN

Sunflowers are tall, cheerful annuals grown for their edible seeds and as pollinator magnets. They come in sizes from 2-foot dwarfs to 12-foot giants.

Rush County, Indiana is in USDA Zone 6a. The average last spring frost is April 14 and the first fall frost is October 21, giving you a growing season of approximately 190 days.

At an elevation of 1,033 feet, Rush County receives approximately 41.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88ยฐF, providing good warmth for Sunflower during the growing season.

Rush County, IN (Zone 6a) Moderate season
190 days
Last Spring Frost April 14
190 growing days
First Fall Frost October 21

Rush County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (58 days to spare)
Start indoors: Feb 11 Transplant: Apr 22 🍅 Harvest: Jul 1 – Aug 19
Recommended (50%) ✓ Fits season (57 days to spare)
Start indoors: Feb 17 Transplant: Apr 28 🍅 Harvest: Jul 7 – Aug 25
Safe Start (90%) ✓ Fits season (51 days to spare)
Start indoors: Mar 6 Transplant: May 15 🍅 Harvest: Jul 24 – Sep 11

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
0.5″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

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

Sunflower needs ~1,360 GDD — county provides 3,040 GDD Excellent fit

Sunflower Planting Timeline โ€” Rush County, IN

Sunflower Planting Calendar

Activity When Date Range
Start Indoors February 17 Feb 17 โ€“ Mar 3
Transplant Outdoors April 28 Apr 28 โ€“ May 12
Direct Sow April 21 Apr 21 โ€“ May 12
Harvest July 7 Jul 7 โ€“ Aug 25

Plant 1" deep ยท 18" apart ยท Rows 30" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Low โ€” drought tolerant

Days to Maturity

70โ€“100 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 6a

Growing Season

190 days

Growing Tips for Rush County

Direct sow after last frost. Stake tall varieties in windy areas. Harvest seed heads when the back turns brown and seeds are plump. Dry heads upside down.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Level Up Your Garden

Frequently Asked Questions

When should I plant Sunflower in Rush County, IN?

Rush County is in Zone 6a with an average last frost of April 14. Plan your Sunflower planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Rush County, IN?

Rush County, Indiana is in USDA Hardiness Zone 6a. The average last spring frost is April 14 and first fall frost is October 21.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Rush 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 Rush County, IN. Local conditions may vary. Last updated: April 2026.