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When to Plant Comfrey in Jefferson County, OH

Jefferson County, Ohio Zone 6b May

May in Jefferson County, Ohio — your action list

A quick May briefing for Jefferson County, Ohio gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 23
Avg. first frost October 29
Soil temp (4") 62°F
Watering Low
Pest pressure Low
Daylight 14.2 hrs

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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.

Jefferson County, Ohio is in USDA Zone 6b. The average last spring frost is April 23 and the first fall frost is October 29, giving you a growing season of approximately 189 days.

At an elevation of 1,017 feet, Jefferson County receives approximately 39.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Comfrey during the growing season.

Jefferson County, OH (Zone 6b) Moderate season
189 days
Last Spring Frost April 23
189 growing days
First Fall Frost October 29
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Jefferson County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (48 days to spare)
Transplant: Apr 21 🍅 Harvest: Jun 23 – Sep 1
Recommended (50%) ✓ Fits season (49 days to spare)
Transplant: Apr 30 🍅 Harvest: Jul 2 – Sep 10
Safe Start (90%) ✓ Fits season (44 days to spare)
Transplant: May 16 🍅 Harvest: Jul 18 – Sep 26

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 Jefferson County

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

Soil pH

Your soil pH (5.9–7.1) overlaps with Comfrey's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Comfrey.

Organic Matter

Organic matter is excellent (4.9%) — Comfrey will thrive.

How to Plant Comfrey

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

Succession Planting Comfrey

3
successive plantings in your 189-day season

Sow every 6.9 weeks. Last sowing by Jul 31 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 695 gal / 100 sq ft

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 1.6" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 4.3" 3.6" 0.7" 💧 Light watering
May 4.3" 4.5" 0" ✅ Rainfall sufficient
Jun 4.3" 4.6" 0" ✅ Rainfall sufficient
Jul 4.3" 5.2" 0" ✅ Rainfall sufficient
Aug 4.3" 4.2" 0.1" 💧 Light watering
Sep 4.3" 3.6" 0.7" 💧 Light watering
Oct 4.3" 3.3" 1" 💧 Light watering
Nov 2.8" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Jefferson 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 ~1,088 GDD — county provides 2,740 GDD Excellent fit

Comfrey Planting Timeline — Jefferson County, OH

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors April 30 Apr 30 – May 14
Harvest July 2 Jul 2 – Sep 10

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Transplant Outdoors
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

1"/week · 1-2 times/week

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

189 days in Jefferson County

Growing Tips for Comfrey in Jefferson County

Direct sow Comfrey outdoors after April 23 in Jefferson 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 →

Frequently Asked Questions

When should I plant Comfrey in Jefferson County, OH?

Jefferson County is in Zone 6b with an average last frost of April 23. Plan your Comfrey planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jefferson County, OH?

Jefferson County, Ohio is in USDA Hardiness Zone 6b. The average last spring frost is April 23 and first fall frost is October 29.

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Your Jefferson County Garden Planner — Free

A 24-page printable planner built for Jefferson 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 Jefferson County, OH. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.