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When to Plant Echinacea in Boone County, IA

Boone County, Iowa Zone 5a May

May in Boone County, Iowa — your action list

Your Boone County, Iowa garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost April 28
Avg. first frost October 6
Soil temp (4") 60°F
Watering Low
Pest pressure Low
Daylight 14.4 hrs
  1. Get echinacea in the ground

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

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Echinacea (purple coneflower) is a native prairie perennial valued for its immune-supporting properties and beautiful daisy-like flowers that attract pollinators.

Boone County, Iowa is in USDA Zone 5a. The average last spring frost is April 28 and the first fall frost is October 6, giving you a growing season of approximately 161 days.

At an elevation of 950 feet, Boone County receives approximately 30.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Echinacea during the growing season.

Boone County, IA (Zone 5a) Moderate season
161 days
Last Spring Frost April 28
161 growing days
First Fall Frost October 6

Boone County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Apr 29 🍅 Harvest: Sep 2 – Oct 14
Recommended (50%) ✗ May not fit
Transplant: May 5 🍅 Harvest: Sep 8 – Oct 20
Safe Start (90%) ✗ May not fit
Transplant: May 19 🍅 Harvest: Sep 22 – Nov 3

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 Boone County

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

Soil pH

Your soil pH (6.1–6.9) is within Echinacea's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.2%) — Echinacea will thrive.

How to Plant Echinacea

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.8″/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 Echinacea

Echinacea 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 Echinacea Needs Rainfall You Supplement Action
Jan 1.2" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 2.2" 2.9" 0" ✅ Rainfall sufficient
May 2.2" 3.8" 0" ✅ Rainfall sufficient
Jun 2.2" 3.5" 0" ✅ Rainfall sufficient
Jul 2.2" 3.2" 0" ✅ Rainfall sufficient
Aug 2.2" 3.4" 0" ✅ Rainfall sufficient
Sep 2.2" 2.8" 0" ✅ Rainfall sufficient
Oct 2.2" 2.5" 0" ✅ Rainfall sufficient
Nov 2.2" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Boone County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Echinacea 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.

Echinacea needs ~2,062 GDD — county provides 2,213 GDD Good fit

Echinacea Planting Timeline — Boone County, IA

Echinacea Planting Calendar

Activity When Date Range
Transplant Outdoors May 5 May 5 – May 19
Harvest September 8 Sep 8 – Oct 20

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June
July
August
September Harvest
October Harvest
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

120–180 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 5a

📆 Growing Season

161 days in Boone County

Growing Tips for Echinacea in Boone County

Direct sow Echinacea outdoors after April 28 in Boone County when soil has warmed and frost danger has passed.

Your 161.0-day growing season in Boone County is tight for Echinacea (120.0-180.0 days to maturity). Start indoors and choose early-maturing varieties.

Common pests for Echinacea 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 in fall for spring germination. Seeds need cold stratification. Deadhead to prolong blooming or leave seed heads for birds.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Echinacea in Boone County, IA?

Boone County is in Zone 5a with an average last frost of April 28. Plan your Echinacea planting based on this frost date — see the calendar above for exact timing.

What planting zone is Boone County, IA?

Boone County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 28 and first fall frost is October 6.

🌱

Your Boone County Garden Planner — Free

A 24-page printable planner built for Boone 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 Boone County, IA. Local conditions may vary. Last updated: May 2026.

Sources & credits

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