When to plant Cosmos in Hardin County, IL
Aim to plant Cosmos in Hardin County on or after April 4; the window stays open through April 25. Hardin County's 210-day frost-free season gives you enough for a full main crop and a short fall succession.
When to Plant Cosmos in Hardin County, IL
Cosmos (Cosmos bipinnatus) is an airy, feathery-foliaged cottage garden annual from Mexico that thrives on neglect. It produces delicate daisy-like blooms in shades of pink, white, and magenta from midsummer until frost. Cosmos is a prolific self-sower — once established in a garden it often returns year after year without replanting. Excellent habitat plant for beneficial insects.
Hardin County, Illinois is in USDA Zone 7a. The average last spring frost is April 4 and the first fall frost is October 31, giving you a growing season of approximately 210 days.
At an elevation of 1,218 feet, Hardin County receives approximately 30.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Cosmos during the growing season.
Hardin County Soil Profile
Soil Type
Silt Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Cosmos Planting Timeline — Hardin County, IL
Cosmos Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 7 | Mar 7 – Mar 21 |
| Transplant Outdoors | April 4 | Apr 4 – Apr 18 |
| Direct Sow | April 4 | Apr 4 – Apr 25 |
| Bloom | June 13 | Jun 13 – Oct 3 |
Plant 0.3" deep · 12" apart · Rows 18" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow |
| May | — |
| June | Bloom |
| 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
60–90 days
🧪 Soil pH
Needs 6–8 · Your soil: N/A
🗺️ USDA Zone
Zone 7a
📆 Growing Season
210 days in Hardin County
Growing Tips for Hardin County
Direct-sow after last frost; cosmos germinates readily at 65-80°F in 7-10 days. Avoid rich soil — excess fertility produces lush foliage at the expense of blooms. Cosmos tolerates poor, dry soil exceptionally well. Pinch seedlings at 8 inches to encourage branching. Self-sows freely; allow some seed heads to mature and drop for a no-fuss perennial effect in warm climates.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Cosmos in Other Locations
Frequently Asked Questions
When should I plant Cosmos in Hardin County, IL?
Hardin County is in Zone 7a with an average last frost of April 4. Plan your Cosmos planting based on this frost date — see the calendar above for exact timing.
What planting zone is Hardin County, IL?
Hardin County, Illinois is in USDA Hardiness Zone 7a. The average last spring frost is April 4 and first fall frost is October 31.
When should I plant Cosmos in Hardin County, IL?
In Hardin County, IL, plant Cosmos after the last frost (around April 4) and before the first frost (around October 31). Best results when soil holds above 50°F.
What growing zone is Hardin County, IL for Cosmos?
Hardin County sits in USDA Zone 7a. Cosmos grows reliably in zones 2a through 11b, so it's a good fit here.
Can Cosmos grow in Hardin County's climate?
Yes — Cosmos grows well in Hardin County's temperate climate. Hardin County averages a 210-day frost-free season, with last frost around April 4 and first frost around October 31.
Your Hardin County Garden Planner — Free
A 22-page printable planner built for Hardin County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.