When to plant Sunflower in Marshall County, IN
Marshall County gardeners should plant Sunflower between May 3 and May 24 in spring. With Marshall County's Zone 6a climate (last frost April 26), Sunflower needs 70–100 days to mature — plant by July 10 for a full harvest.
When to Plant Sunflower in Marshall 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.
Marshall County, Indiana is in USDA Zone 6a. The average last spring frost is April 26 and the first fall frost is October 18, giving you a growing season of approximately 175 days.
At an elevation of 1,140 feet, Marshall County receives approximately 34.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Sunflower to ensure they mature before fall.
Marshall County Soil Profile
Soil Type
Silt Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Sunflower Planting Timeline — Marshall County, IN
Sunflower Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 5 | Apr 5 – Apr 19 |
| Transplant Outdoors | May 3 | May 3 – May 17 |
| Direct Sow | May 3 | May 3 – May 24 |
| Bloom | July 26 | Jul 26 – Oct 18 |
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
175 days in Marshall County
Growing Tips for Marshall 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 Marshall County, IN?
Marshall County is in Zone 6a with an average last frost of April 26. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.
What planting zone is Marshall County, IN?
Marshall County, Indiana is in USDA Hardiness Zone 6a. The average last spring frost is April 26 and first fall frost is October 18.
When should I plant Sunflower in Marshall County, IN?
In Marshall County, IN, plant Sunflower after the last frost (around April 26) and before the first frost (around October 18). Best results when soil holds above 50°F.
What growing zone is Marshall County, IN for Sunflower?
Marshall 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 Marshall County's climate?
Yes — Sunflower grows well in Marshall County's temperate climate. Marshall County averages a 175-day frost-free season, with last frost around April 26 and first frost around October 18.
Your Marshall County Garden Planner — Free
A 22-page printable planner built for Marshall 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.