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When to plant Comfrey in Deckerville, MI

Deckerville's short 166-day growing season means one Comfrey planting between May 11 and May 25. No fall crop in Zone 6a.

When to Plant Comfrey in Deckerville, MI

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

Deckerville, Michigan is in USDA Zone 6a. The average last spring frost is May 4 and the first fall frost is October 17, giving you a growing season of approximately 166 days.

At an elevation of 985 feet, Sanilac County receives approximately 37 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Comfrey during the growing season.

Deckerville, MI (Zone 6a) Moderate season
166 days
Last Spring Frost May 4
166 growing days
First Fall Frost October 17

Deckerville Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-7

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 1.3" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 3.9" 0" ❄️ Dormant
May 4.3" 3.9" 0.4" 💧 Light watering
Jun 4.3" 4.9" 0" ✅ Rainfall sufficient
Jul 4.3" 4.5" 0" ✅ Rainfall sufficient
Aug 4.3" 3.4" 0.9" 💧 Light watering
Sep 4.3" 3.8" 0.5" 💧 Light watering
Oct 4.3" 2.8" 1.5" 💧 Light watering
Nov 2.3" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

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

Comfrey Planting Timeline — Deckerville, MI

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors May 11 May 11 – May 25
Harvest July 13 Jul 13 – Sep 21

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 6a

📆 Growing Season

166 days in Sanilac County

Growing Tips for Deckerville

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 →

When should I plant Comfrey in Deckerville, MI?

In Deckerville, MI, plant Comfrey after the last frost (around May 4) and before the first frost (around October 17). Best results when soil holds above 50°F.

What growing zone is Deckerville, MI for Comfrey?

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

Can Comfrey grow in Deckerville's climate?

Yes — Comfrey grows well in Deckerville's temperate climate. Deckerville averages a 166-day frost-free season, with last frost around May 4 and first frost around October 17.

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Your Sanilac County Garden Planner — Free

A 22-page printable planner built for Sanilac County (Zone 6a). 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 Sanilac County, MI. Local conditions may vary. Last updated: July 2026.