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When to plant Comfrey in Boone County County,

In Boone County County, Comfrey is a spring-only crop. Plant April 30–May 14 once soil hits 50°F.

When to Plant Comfrey in Boone County, IL

Comfrey is a vigorous perennial herb valued as a dynamic accumulator of nutrients. Its leaves make excellent mulch, compost activator, and liquid fertilizer.

Boone County, Illinois is in USDA Zone 5b. The average last spring frost is April 23 and the first fall frost is October 16, giving you a growing season of approximately 176 days.

At an elevation of 512 feet, Boone County receives approximately 39.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Comfrey to ensure they mature before fall.

Boone County, IL (Zone 5b) Moderate season
176 days
Last Spring Frost April 23
176 growing days
First Fall Frost October 16

Boone County Soil Profile

Soil Type

Silt Loam

Soil pH

6-6.8

Drainage

Well Drained

Monthly Watering Guide for Comfrey

Comfrey needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Comfrey Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 4.3" 3.4" 0.9" 💧 Light watering
May 4.3" 4.1" 0.2" 💧 Light watering
Jun 4.3" 5.7" 0" ✅ Rainfall sufficient
Jul 4.3" 4.9" 0" ✅ Rainfall sufficient
Aug 4.3" 3.8" 0.5" 💧 Light watering
Sep 4.3" 3.5" 0.8" 💧 Light watering
Oct 4.3" 3.5" 0.8" 💧 Light watering
Nov 2.9" 0" ❄️ Dormant
Dec 2.3" 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.

Comfrey Planting Timeline — Boone County, IL

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors April 30 Apr 30 – May 14
Harvest July 2 Jul 2 – Sep 10

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 5b

📆 Growing Season

176 days in Boone County

Growing Tips for Boone County

Plant root cuttings 2 inches deep. Choose Bocking 14 variety to prevent self-seeding. Cut leaves 3-4 times per season for mulch or compost. Avoid planting near pathways as it spreads.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Comfrey in Boone County, IL?

Boone County is in Zone 5b with an average last frost of April 23. Plan your Comfrey planting based on this frost date — see the calendar above for exact timing.

What planting zone is Boone County, IL?

Boone County, Illinois is in USDA Hardiness Zone 5b. The average last spring frost is April 23 and first fall frost is October 16.

When should I plant Comfrey in Boone County County, ?

In Boone County County, , plant Comfrey after the last frost (around April 23) and before the first frost (around October 16). Best results when soil holds above 50°F.

What growing zone is Boone County County, for Comfrey?

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

Can Comfrey grow in Boone County County's climate?

Yes — Comfrey grows well in Boone County County's temperate climate. Boone County County averages a 176-day frost-free season, with last frost around April 23 and first frost around October 16.

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Your Boone County Garden Planner — Free

A 22-page printable planner built for Boone County (Zone 5b). 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, IL. Local conditions may vary. Last updated: June 2026.

Sources & credits

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