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When to plant Coreopsis in Cedar County County,

Cedar County County's climate puts the Coreopsis spring window between April 24 and May 15. time plantings around the expected last-frost window for best survival.

When to Plant Coreopsis in Cedar County, IA

Cedar County, Iowa Zone 5a June

June to-do list for Cedar County, Iowa

Your garden in Cedar County, Iowa is working on a schedule, even when you're not. Here's where you should be this June.

Avg. last frost April 17
Avg. first frost October 16
Soil temp (4") 70°F
Watering Low
Pest pressure High
Daylight 15 hrs
  1. Start coreopsis indoors

    Label every cell. You will absolutely forget which is which otherwise.

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.

Cedar County, Iowa is in USDA Zone 5a. The average last spring frost is April 17 and the first fall frost is October 16, giving you a growing season of approximately 182 days.

At an elevation of 1,112 feet, Cedar County receives approximately 41 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Coreopsis during the growing season.

Perennial Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Cedar County, IA (Zone 5a) Moderate season
182 days
Last Spring Frost April 17
182 growing days
First Fall Frost October 16

Cedar County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.9

Drainage

Well Drained

Coreopsis Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Feb 8 Transplant: Apr 26 🌸 Bloom: Jul 5 – Oct 11
Recommended (50%) ✓ Fits season (0 days to spare)
Start indoors: Feb 13 Transplant: May 1 🌸 Bloom: Jul 10 – Oct 16
Safe Start (90%) ✗ May not fit
Start indoors: Mar 6 Transplant: May 22 🌸 Bloom: Jul 31 – Nov 6

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 Cedar County

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

Soil pH

Your soil pH (5.9–6.9) is within Coreopsis's preferred range (5.5–7.5).

Soil Texture

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

Drainage

Drainage is adequate for Coreopsis.

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Coreopsis.

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 28 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 1.5" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 2.2" 3.4" 0" ✅ Rainfall sufficient
May 2.2" 5.1" 0" ✅ Rainfall sufficient
Jun 2.2" 5.3" 0" ✅ Rainfall sufficient
Jul 2.2" 4.9" 0" ✅ Rainfall sufficient
Aug 2.2" 4.7" 0" ✅ Rainfall sufficient
Sep 2.2" 3.5" 0" ✅ Rainfall sufficient
Oct 2.2" 3.2" 0" ✅ Rainfall sufficient
Nov 3" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Cedar 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 ~1,068 GDD — county provides 2,775 GDD Excellent fit

Coreopsis Planting Timeline — Cedar County, IA

Coreopsis Planting Calendar

Activity When Date Range
Start Indoors February 13 Feb 13 – Feb 27
Transplant Outdoors May 1 May 1 – May 15
Direct Sow April 24 Apr 24 – May 15
Bloom July 10 Jul 10 – Oct 16

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March
April Direct Sow
May Transplant Outdoors Direct Sow
June
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 5a

📆 Growing Season

182 days in Cedar County

Growing Tips for Coreopsis in Cedar County

Direct sow Coreopsis outdoors after April 17 in Cedar 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 Cedar County, IA?

Cedar County is in Zone 5a with an average last frost of April 17. Plan your Coreopsis planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cedar County, IA?

Cedar County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 17 and first fall frost is October 16.

When should I plant Coreopsis in Cedar County County, ?

In Cedar County County, , plant Coreopsis after the last frost (around April 17) and before the first frost (around October 16). Best results when soil holds above 50°F.

What growing zone is Cedar County County, for Coreopsis?

Cedar County County sits in USDA Zone 5a. Coreopsis grows reliably in zones 3a through 9b, so it's a good fit here.

Can Coreopsis grow in Cedar County County's climate?

Yes — Coreopsis grows well in Cedar County County's temperate climate. Cedar County County averages a 182-day frost-free season, with last frost around April 17 and first frost around October 16.

🌱

Your Cedar County Garden Planner — Free

A 22-page printable planner built for Cedar County (Zone 5a). 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 Cedar County, IA. 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.