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When to plant Comfrey in Aitkin County, MN

Plant Comfrey in Aitkin County during the brief May 16–May 30 window. With 147 frost-free days, fall plantings can't mature before October 3.

When to Plant Comfrey in Aitkin 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.

Aitkin County, Minnesota is in USDA Zone 4a. The average last spring frost is May 9 and the first fall frost is October 3, giving you a growing season of approximately 147 days.

At an elevation of 1,188 feet, Aitkin County receives approximately 35 inches of rainfall annually with predominantly silt loam soil. Summer highs average 78°F, so choose short-season varieties of Comfrey to ensure they mature before fall.

Aitkin County, MN (Zone 4a) Short season
147 days
Last Spring Frost May 9
147 growing days
First Fall Frost October 3

Aitkin County Soil Profile

Soil Type

Silt Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Comfrey Planting Timeline — Aitkin County, MN

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors May 16 May 16 – May 30
Harvest July 18 Jul 18 – Sep 26

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

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 4a

📆 Growing Season

147 days in Aitkin County

Growing Tips for Aitkin 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 Aitkin County, MN?

Aitkin County is in Zone 4a with an average last frost of May 9. Plan your Comfrey planting based on this frost date — see the calendar above for exact timing.

What planting zone is Aitkin County, MN?

Aitkin County, Minnesota is in USDA Hardiness Zone 4a. The average last spring frost is May 9 and first fall frost is October 3.

When should I plant Comfrey in Aitkin County, MN?

In Aitkin County, MN, plant Comfrey after the last frost (around May 9) and before the first frost (around October 3). Best results when soil holds above 50°F.

What growing zone is Aitkin County, MN for Comfrey?

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

Can Comfrey grow in Aitkin County's climate?

Yes — Comfrey grows well in Aitkin County's temperate climate. Aitkin County averages a 147-day frost-free season, with last frost around May 9 and first frost around October 3.

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Your Aitkin County Garden Planner — Free

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

Sources & credits

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