When to plant Cosmos in Saline County, IL
Spring Cosmos in Saline County goes in April 8–April 29, once nighttime temps stop dipping near freezing.
When to Plant Cosmos in Saline County, IL
June in the garden — Saline County, Illinois
Here's what deserves your attention in Saline County, Illinois this month. Everything below is tailored to Zone 7a and timed around your local frost dates.
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Collect cosmos at their peak
If you can't use it all right away, check the food-preservation section of your planner.
To set up a strong July, finish these tasks
- First harvests: cosmos
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.
Saline County, Illinois is in USDA Zone 7a. The average last spring frost is April 8 and the first fall frost is October 24, giving you a growing season of approximately 199 days.
At an elevation of 748 feet, Saline County receives approximately 41.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Cosmos during the growing season.
Saline County Soil Profile
Soil Type
Silt Loam
Soil pH
6-6.7
Drainage
Well Drained
Cosmos 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.
Soil Compatibility in Saline County
How your county's soil matches Cosmos's growing requirements.
Soil pH
Your soil pH (6.0–6.7) is within Cosmos's preferred range (6.0–8.0).
Soil Texture
The silt loam soil in Saline County is excellent for Cosmos — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.9%). Annual compost additions will help Cosmos.
How to Plant Cosmos
Succession Planting Cosmos
Sow every 6.9 weeks. Last sowing by Jul 26 to harvest before frost.
Cosmos Water Budget
Monthly Watering Guide for Cosmos
Cosmos needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.
| Month | Cosmos Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.7" | 0" | ❄️ Dormant |
| Feb | — | 2" | 0" | ❄️ Dormant |
| Mar | — | 3.2" | 0" | ❄️ Dormant |
| Apr | 2.2" | 4.3" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 4.7" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 4.6" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 4.8" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 4.5" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 3.2" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 2.9" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2.9" | 0" | ❄️ Dormant |
| Dec | — | 2.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Saline County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Cosmos Heat Requirements (GDD)
What are Growing Degree Days (GDD)?
Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.
Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.
Cosmos Planting Timeline — Saline County, IL
Cosmos Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 11 | Mar 11 – Mar 25 |
| Transplant Outdoors | April 8 | Apr 8 – Apr 22 |
| Direct Sow | April 8 | Apr 8 – Apr 29 |
| Bloom | June 17 | Jun 17 – Oct 7 |
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
0.5"/week · Natural rainfall sufficient
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–8 · Your soil: ideal
🗺️ USDA Zone
Zone 7a
📆 Growing Season
199 days in Saline County
Growing Tips for Cosmos in Saline County
Direct sow Cosmos outdoors after April 08 in Saline County when soil has warmed and frost danger has passed.
Common pests for Cosmos in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
General growing tips
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 Saline County, IL?
Saline County is in Zone 7a with an average last frost of April 8. Plan your Cosmos planting based on this frost date — see the calendar above for exact timing.
What planting zone is Saline County, IL?
Saline County, Illinois is in USDA Hardiness Zone 7a. The average last spring frost is April 8 and first fall frost is October 24.
When should I plant Cosmos in Saline County, IL?
In Saline County, IL, plant Cosmos after the last frost (around April 8) and before the first frost (around October 24). Best results when soil holds above 50°F.
What growing zone is Saline County, IL for Cosmos?
Saline 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 Saline County's climate?
Yes — Cosmos grows well in Saline County's temperate climate. Saline County averages a 199-day frost-free season, with last frost around April 8 and first frost around October 24.
Your Saline County Garden Planner — Free
A 22-page printable planner built for Saline 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.