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When to plant Comfrey in Grayling, MI

Grayling's short 130-day growing season means one Comfrey planting between May 29 and June 12. No fall crop in Zone 5a.

When to Plant Comfrey in Grayling, MI

Crawford County, Michigan Zone 5a July

Your July planting checklist for Crawford County, Michigan

We've pulled the most time-sensitive tasks for Crawford County, Michigan this July and put them front and centre. Tackle them in order.

Avg. last frost May 22
Avg. first frost September 29
Soil temp (4") 73°F
Watering Low
Pest pressure High
Daylight 15.1 hrs
  1. Bring in the comfrey

    If you can't use it all right away, check the food-preservation section of your planner.

To set up a strong August, finish these tasks
  • First harvests: comfrey

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

Grayling, Michigan is in USDA Zone 5a. The average last spring frost is May 22 and the first fall frost is September 29, giving you a growing season of approximately 130 days.

At an elevation of 894 feet, Crawford County receives approximately 34.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Comfrey to ensure they mature before fall.

Grayling, MI (Zone 5a) Short season
130 days
Last Spring Frost May 22
130 growing days
First Fall Frost September 29

Grayling Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7

Drainage

Well Drained

Comfrey Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 25 🍅 Harvest: Jul 27 – Oct 5
Recommended (50%) ✗ May not fit
Transplant: May 29 🍅 Harvest: Jul 31 – Oct 9
Safe Start (90%) ✗ May not fit
Transplant: Jun 10 🍅 Harvest: Aug 12 – Oct 21

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Soil Compatibility in Grayling

How your county's soil matches Comfrey's growing requirements.

Soil pH

Your soil pH (5.9–7.0) overlaps with Comfrey's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Crawford County is excellent for Comfrey — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.8%) — Comfrey will thrive.

How to Plant Comfrey

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Comfrey

2
successive plantings in your 130-day season

Sow every 6.9 weeks. Last sowing by Jul 01 to harvest before frost.

Comfrey Water Budget

Plant needs
1.0″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.6" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 3" 0" ❄️ Dormant
May 4.3" 4.4" 0" ✅ Rainfall sufficient
Jun 4.3" 4.2" 0.1" 💧 Light watering
Jul 4.3" 3.8" 0.5" 💧 Light watering
Aug 4.3" 3.9" 0.4" 💧 Light watering
Sep 4.3" 2.8" 1.5" 💧 Light watering
Oct 2.6" 0" ❄️ Dormant
Nov 2.2" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

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

Comfrey Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Comfrey needs ~806 GDD — county provides 1,397 GDD Excellent fit

Comfrey Planting Timeline — Grayling, MI

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors May 29 May 29 – Jun 12
Harvest July 31 Jul 31 – Oct 9

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

130 days in Crawford County

Growing Tips for Comfrey in Grayling

Direct sow Comfrey outdoors after May 22 in Crawford County when soil has warmed and frost danger has passed.

General growing tips

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 Grayling, MI?

In Grayling, MI, plant Comfrey after the last frost (around May 22) and before the first frost (around September 29). Best results when soil holds above 50°F.

What growing zone is Grayling, MI for Comfrey?

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

Can Comfrey grow in Grayling's climate?

Yes — Comfrey grows well in Grayling's temperate climate. Grayling averages a 130-day frost-free season, with last frost around May 22 and first frost around September 29.

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Your Crawford County Garden Planner — Free

A 22-page printable planner built for Crawford County (Zone 5a). 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 Crawford County, MI. Local conditions may vary. Last updated: July 2026.