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When to plant Coreopsis in Edgar County County,

In Zone 6a (Edgar County County), direct-sow Coreopsis between April 25 and May 16 for spring, after the April 18 last-frost mark.

When to Plant Coreopsis in Edgar County, IL

Edgar County, Illinois Zone 6a June

Your June game plan for Edgar County, Illinois

Welcome to June in Zone 6a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 18
Avg. first frost October 17
Soil temp (4") 70°F
Watering Low
Pest pressure High
Daylight 14.8 hrs
  1. Start coreopsis indoors

    Starting these indoors now means sturdy transplants ready the moment your soil warms up.

July prep starts now
  • First harvests: coreopsis

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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.

Edgar County, Illinois is in USDA Zone 6a. The average last spring frost is April 18 and the first fall frost is October 17, giving you a growing season of approximately 182 days.

At an elevation of 1,272 feet, Edgar County receives approximately 41.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Coreopsis to ensure they mature before fall.

Perennial Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Edgar County, IL (Zone 6a) Moderate season
182 days
Last Spring Frost April 18
182 growing days
First Fall Frost October 17
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Edgar County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.8

Drainage

Well Drained

Coreopsis Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Feb 9 Transplant: Apr 20 🌸 Bloom: Jun 29 – Oct 19
Recommended (50%) ✗ May not fit
Start indoors: Feb 14 Transplant: Apr 25 🌸 Bloom: Jul 4 – Oct 24
Safe Start (90%) ✗ May not fit
Start indoors: Mar 2 Transplant: May 11 🌸 Bloom: Jul 20 – Nov 9

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 Edgar County

How your county's soil matches Coreopsis's growing requirements.

Soil pH

Your soil pH (5.9–6.8) is within Coreopsis's preferred range (5.5–7.5).

Soil Texture

The silt loam soil in Edgar County is excellent for Coreopsis — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.3%) — Coreopsis will thrive.

How to Plant Coreopsis

0.1"
Planting Depth
18"
Between Plants
24"
Between Rows

Succession Planting Coreopsis

3
successive plantings in your 182-day season

Sow every 6.9 weeks. Last sowing by Jul 29 to harvest before frost.

Coreopsis Water Budget

Plant needs
0.5″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.6" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 2.2" 3.8" 0" ✅ Rainfall sufficient
May 2.2" 4.8" 0" ✅ Rainfall sufficient
Jun 2.2" 5.5" 0" ✅ Rainfall sufficient
Jul 2.2" 4.9" 0" ✅ Rainfall sufficient
Aug 2.2" 3.8" 0" ✅ Rainfall sufficient
Sep 2.2" 3.9" 0" ✅ Rainfall sufficient
Oct 2.2" 3.3" 0" ✅ Rainfall sufficient
Nov 2.9" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Edgar 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 needs ~858 GDD — county provides 2,229 GDD Excellent fit

Coreopsis Planting Timeline — Edgar County, IL

Coreopsis Planting Calendar

Activity When Date Range
Start Indoors February 14 Feb 14 – Feb 28
Transplant Outdoors April 25 Apr 25 – May 9
Direct Sow April 25 Apr 25 – May 16
Bloom July 4 Jul 4 – Oct 24

Plant 0.1" deep · 18" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March
April Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June
July Bloom
August Bloom
September Bloom
October Bloom
November
December
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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 6a

📆 Growing Season

182 days in Edgar County

Growing Tips for Coreopsis in Edgar County

Direct sow Coreopsis outdoors after April 18 in Edgar 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 →

Frequently Asked Questions

When should I plant Coreopsis in Edgar County, IL?

Edgar County is in Zone 6a with an average last frost of April 18. Plan your Coreopsis planting based on this frost date — see the calendar above for exact timing.

What planting zone is Edgar County, IL?

Edgar County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 18 and first fall frost is October 17.

When should I plant Coreopsis in Edgar County County, ?

In Edgar County County, , plant Coreopsis after the last frost (around April 18) and before the first frost (around October 17). Best results when soil holds above 50°F.

What growing zone is Edgar County County, for Coreopsis?

Edgar County County sits in USDA Zone 6a. Coreopsis grows reliably in zones 3a through 9b, so it's a good fit here.

Can Coreopsis grow in Edgar County County's climate?

Yes — Coreopsis grows well in Edgar County County's temperate climate. Edgar County County averages a 182-day frost-free season, with last frost around April 18 and first frost around October 17.

🌱

Your Edgar County Garden Planner — Free

A 22-page printable planner built for Edgar 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.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Edgar County, IL. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.