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When to plant Comfrey in Bonner County County,

Bonner County County's short 151-day growing season means one Comfrey planting between May 12 and May 26. No fall crop in Zone 6b.

When to Plant Comfrey in Bonner County, ID

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

Bonner County, Idaho is in USDA Zone 6b. The average last spring frost is May 5 and the first fall frost is October 3, giving you a growing season of approximately 151 days.

At an elevation of 7,480 feet, Bonner County receives approximately 12.9 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Comfrey during the growing season. With low rainfall, drip irrigation is essential for growing Comfrey successfully. Mulch heavily to conserve soil moisture.

Bonner County, ID (Zone 6b) Moderate season
151 days
Last Spring Frost May 5
151 growing days
First Fall Frost October 3
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Bonner County Soil Profile

Soil Type

Loam

Soil pH

6.4-8.2

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 0.9" 0" ❄️ Dormant
Feb 0.7" 0" ❄️ Dormant
Mar 1.1" 0" ❄️ Dormant
Apr 1.5" 0" ❄️ Dormant
May 4.3" 1.5" 2.8" 🚿 Regular watering
Jun 4.3" 0.9" 3.4" 🚿 Regular watering
Jul 4.3" 1.1" 3.2" 🚿 Regular watering
Aug 4.3" 1.2" 3.1" 🚿 Regular watering
Sep 4.3" 1.1" 3.2" 🚿 Regular watering
Oct 4.3" 1.1" 3.2" 🚿 Regular watering
Nov 0.9" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

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

Comfrey Planting Timeline — Bonner County, ID

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors May 12 May 12 – May 26
Harvest July 14 Jul 14 – Sep 22

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June
July Harvest
August Harvest
September Harvest
October
November
December
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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 6b

📆 Growing Season

151 days in Bonner County

Growing Tips for Bonner 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 Bonner County, ID?

Bonner County is in Zone 6b with an average last frost of May 5. Plan your Comfrey planting based on this frost date — see the calendar above for exact timing.

What planting zone is Bonner County, ID?

Bonner County, Idaho is in USDA Hardiness Zone 6b. The average last spring frost is May 5 and first fall frost is October 3.

When should I plant Comfrey in Bonner County County, ?

In Bonner County County, , plant Comfrey after the last frost (around May 5) and before the first frost (around October 3). Best results when soil holds above 50°F.

What growing zone is Bonner County County, for Comfrey?

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

Can Comfrey grow in Bonner County County's climate?

Yes — Comfrey grows well in Bonner County County's temperate climate. Bonner County County averages a 151-day frost-free season, with last frost around May 5 and first frost around October 3.

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Your Bonner County Garden Planner — Free

A 22-page printable planner built for Bonner 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.

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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 Bonner County, ID. Local conditions may vary. Last updated: June 2026.

Sources & credits

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