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When to plant Comfrey in Grant County County,

Plant Comfrey in Grant County County, between May 8 and May 22 — the only viable window. Zone 4b's short season (159 frost-free days) rules out a fall crop.

When to Plant Comfrey in Grant County, MN

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

Grant County, Minnesota is in USDA Zone 4b. The average last spring frost is May 1 and the first fall frost is October 7, giving you a growing season of approximately 159 days.

At an elevation of 1,371 feet, Grant County receives approximately 31.4 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.

Grant County, MN (Zone 4b) Moderate season
159 days
Last Spring Frost May 1
159 growing days
First Fall Frost October 7
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Grant County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.8

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 1.4" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 2.8" 0" ❄️ Dormant
May 4.3" 4.1" 0.2" 💧 Light watering
Jun 4.3" 4.4" 0" ✅ Rainfall sufficient
Jul 4.3" 3.7" 0.6" 💧 Light watering
Aug 4.3" 2.9" 1.4" 💧 Light watering
Sep 4.3" 3.2" 1.1" 💧 Light watering
Oct 4.3" 2.1" 2.2" 🚿 Regular watering
Nov 1.9" 0" ❄️ Dormant
Dec 1.5" 0" ❄️ Dormant

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

Comfrey Planting Timeline — Grant County, MN

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors May 8 May 8 – May 22
Harvest July 10 Jul 10 – Sep 18

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 4b

📆 Growing Season

159 days in Grant County

Growing Tips for Grant 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 Grant County, MN?

Grant County is in Zone 4b with an average last frost of May 1. Plan your Comfrey planting based on this frost date — see the calendar above for exact timing.

What planting zone is Grant County, MN?

Grant County, Minnesota is in USDA Hardiness Zone 4b. The average last spring frost is May 1 and first fall frost is October 7.

When should I plant Comfrey in Grant County County, ?

In Grant County County, , plant Comfrey after the last frost (around May 1) and before the first frost (around October 7). Best results when soil holds above 50°F.

What growing zone is Grant County County, for Comfrey?

Grant County County sits in USDA Zone 4b. Comfrey grows reliably in zones 3a through 9b, so it's a good fit here.

Can Comfrey grow in Grant County County's climate?

Yes — Comfrey grows well in Grant County County's temperate climate. Grant County County averages a 159-day frost-free season, with last frost around May 1 and first frost around October 7.

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Your Grant County Garden Planner — Free

A 22-page printable planner built for Grant County (Zone 4b). 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 Grant County, MN. Local conditions may vary. Last updated: June 2026.

Sources & credits

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