When to Plant Echinacea in Benton County, IA
Echinacea (purple coneflower) is a native prairie perennial valued for its immune-supporting properties and beautiful daisy-like flowers that attract pollinators.
Benton County, Iowa is in USDA Zone 5a. The average last spring frost is April 28 and the first fall frost is October 9, giving you a growing season of approximately 164 days.
At an elevation of 1,230 feet, Benton County receives approximately 36 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Echinacea during the growing season.
Benton County Soil Profile
Soil Type
Silt Loam
Soil pH
5.9-7
Drainage
Well Drained
Plant Planting Risk Windows
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
Echinacea Planting Timeline — Benton County, IA
Echinacea Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 5 | May 5 – May 19 |
| Harvest | September 8 | Sep 8 – Oct 20 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Transplant Outdoors |
| June | — |
| July | — |
| August | — |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
Sun
Full Sun (6-8+ hours)
Water
Low — drought tolerant
Days to Maturity
120–180 days
Soil pH
6 – 7
USDA Zone
Zone 5a
Growing Season
164 days
Growing Tips for Benton County
Start seeds indoors 8-10 weeks before last frost or direct sow in fall for spring germination. Seeds need cold stratification. Deadhead to prolong blooming or leave seed heads for birds.
Companion Planting
Good Companions
Level Up Your Garden
Echinacea in Other Locations
Frequently Asked Questions
When should I plant Echinacea in Benton County, IA?
Benton County is in Zone 5a with an average last frost of April 28. Plan your Echinacea planting based on this frost date — see the calendar above for exact timing.
What planting zone is Benton County, IA?
Benton County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 28 and first fall frost is October 9.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Benton County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.
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