When to plant Coreopsis in Windsor, IL
Spring Coreopsis in Windsor goes in April 14–May 5, once nighttime temps stop dipping near freezing.
When to Plant Coreopsis in Windsor, IL
June in Shelby County, Illinois — your action list
Your Shelby County, Illinois garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.
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Start coreopsis indoors
Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.
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Start harvesting coreopsis
Check every 1–2 days. Many of these get tough or go to seed if you wait too long.
A few tasks this June that'll pay off in July
- First harvests: coreopsis
Coreopsis (Tickseed) is a cheerful, long-blooming native perennial that produces a continuous flush of bright yellow, gold, or bi-colored daisy-like flowers from early summer well into fall. One of the most reliable cut-and-come-again bloomers in the perennial garden, it thrives in hot, dry, sunny conditions and poor soil where many competitors struggle. An invaluable nectar source for native bees and butterflies, and a butterfly host plant for several species.
Windsor, Illinois is in USDA Zone 6b. The average last spring frost is April 14 and the first fall frost is October 17, giving you a growing season of approximately 186 days.
At an elevation of 807 feet, Shelby County receives approximately 41 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Coreopsis during the growing season.
Windsor Soil Profile
Soil Type
Silt Loam
Soil pH
6.2-7
Drainage
Well Drained
Coreopsis 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 Windsor
How your county's soil matches Coreopsis's growing requirements.
Soil pH
Your soil pH (6.2–7.0) is within Coreopsis's preferred range (5.5–7.5).
Soil Texture
The silt loam soil in Shelby County is excellent for Coreopsis — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.7%) — Coreopsis will thrive.
How to Plant Coreopsis
Succession Planting Coreopsis
Sow every 6.9 weeks. Last sowing by Jul 29 to harvest before frost.
Coreopsis Water Budget
Monthly Watering Guide for Coreopsis
Coreopsis 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 | Coreopsis Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.9" | 0" | ❄️ Dormant |
| Feb | — | 2" | 0" | ❄️ Dormant |
| Mar | — | 2.8" | 0" | ❄️ Dormant |
| Apr | 2.2" | 4.4" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 4.4" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 5.3" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 4" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 4" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 4.2" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 2.9" | 0" | ✅ Rainfall sufficient |
| Nov | — | 3" | 0" | ❄️ Dormant |
| Dec | — | 2.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Shelby County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Coreopsis 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.
Coreopsis Planting Timeline — Windsor, IL
Coreopsis Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 10 | Feb 10 – Feb 24 |
| Transplant Outdoors | April 21 | Apr 21 – May 5 |
| Direct Sow | April 14 | Apr 14 – May 5 |
| Bloom | June 30 | Jun 30 – Oct 27 |
Plant 0.1" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | — |
| April | Transplant Outdoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| 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
60–80 days
🧪 Soil pH
Needs 5.5–7.5 · Your soil: ideal
🗺️ USDA Zone
Zone 6b
📆 Growing Season
186 days in Shelby County
Growing Tips for Coreopsis in Windsor
Direct sow Coreopsis outdoors after April 14 in Shelby County when soil has warmed and frost danger has passed.
Common pests for Coreopsis in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
General growing tips
Start seeds indoors 8–10 weeks before last frost or direct sow after last frost. Seeds germinate easily without stratification. Thrives in poor to average, well-drained soil — rich soil promotes foliage over flowers. Drought tolerant once established; overwatering is the most common mistake. Deadhead spent blooms to maintain continuous flowering through the season. Shear plants by one-third in midsummer for a fresh flush of late-season blooms. Year 2+ plants bloom most heavily. Divide every 2–3 years in early spring to rejuvenate crowded clumps.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Coreopsis in Other Locations
When should I plant Coreopsis in Windsor, IL?
In Windsor, IL, plant Coreopsis after the last frost (around April 14) and before the first frost (around October 17). Best results when soil holds above 50°F.
What growing zone is Windsor, IL for Coreopsis?
Windsor sits in USDA Zone 6b. Coreopsis grows reliably in zones 3a through 9b, so it's a good fit here.
Can Coreopsis grow in Windsor's climate?
Yes — Coreopsis grows well in Windsor's temperate climate. Windsor averages a 186-day frost-free season, with last frost around April 14 and first frost around October 17.
Your Shelby County Garden Planner — Free
A 22-page printable planner built for Shelby County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.