When to plant Sunflower in Cass County, IN
For Cass County, gardeners: plant Sunflower May 1 through May 22 once soil reads 50°F.
When to Plant Sunflower in Cass County, IN
Sunflower (Helianthus annuus) is a fast-growing North American native annual famous for its towering stems and brilliant yellow heads. It thrives in full sun and heat, producing large, pollen-rich blooms that attract bees, butterflies, and seed-eating birds. Varieties range from 18-inch dwarfs to 12-foot giants and nearly every color except blue.
Cass County, Indiana is in USDA Zone 6a. The average last spring frost is April 24 and the first fall frost is October 17, giving you a growing season of approximately 176 days.
At an elevation of 703 feet, Cass County receives approximately 36.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Sunflower to ensure they mature before fall.
Cass County Soil Profile
Soil Type
Silt Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Sunflower Planting Timeline — Cass County, IN
Sunflower Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 3 | Apr 3 – Apr 17 |
| Transplant Outdoors | May 1 | May 1 – May 15 |
| Direct Sow | May 1 | May 1 – May 22 |
| Bloom | July 24 | Jul 24 – Oct 16 |
Plant 1" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Low — drought tolerant
📅 Days to Maturity
70–100 days
🧪 Soil pH
Needs 6–7.5 · Your soil: N/A
🗺️ USDA Zone
Zone 6a
📆 Growing Season
176 days in Cass County
Growing Tips for Cass County
Direct-sow 1 inch deep after last frost; germination takes 7-14 days at 65-75°F soil. Sunflowers dislike root disturbance so direct sowing is strongly preferred over transplanting. Plant in succession every 2 weeks for extended bloom. Stake tall varieties. Avoid overwatering — they tolerate drought once established. Birds will self-deadhead seed heads; leave them up through fall for wildlife.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Sunflower in Other Locations
Frequently Asked Questions
When should I plant Sunflower in Cass County, IN?
Cass County is in Zone 6a with an average last frost of April 24. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.
What planting zone is Cass County, IN?
Cass County, Indiana is in USDA Hardiness Zone 6a. The average last spring frost is April 24 and first fall frost is October 17.
When should I plant Sunflower in Cass County, IN?
In Cass County, IN, plant Sunflower after the last frost (around April 24) and before the first frost (around October 17). Best results when soil holds above 50°F.
What growing zone is Cass County, IN for Sunflower?
Cass County sits in USDA Zone 6a. Sunflower grows reliably in zones 2a through 11b, so it's a good fit here.
Can Sunflower grow in Cass County's climate?
Yes — Sunflower grows well in Cass County's temperate climate. Cass County averages a 176-day frost-free season, with last frost around April 24 and first frost around October 17.
Your Cass County Garden Planner — Free
A 22-page printable planner built for Cass County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.