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When to Plant Comfrey in Seneca County, OH

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

Seneca County, Ohio is in USDA Zone 5b. The average last spring frost is April 25 and the first fall frost is October 22, giving you a growing season of approximately 180 days.

At an elevation of 1,041 feet, Seneca County receives approximately 31.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Comfrey to ensure they mature before fall.

Seneca County, OH (Zone 5b) Moderate season
180 days
Last Spring Frost April 25
180 growing days
First Fall Frost October 22

Seneca County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (41 days to spare)
Transplant: Apr 26 🍅 Harvest: Jun 28 – Sep 6
Recommended (50%) ✓ Fits season (40 days to spare)
Transplant: May 2 🍅 Harvest: Jul 4 – Sep 12
Safe Start (90%) ✓ Fits season (42 days to spare)
Transplant: May 11 🍅 Harvest: Jul 13 – Sep 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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 413 gal / 100 sq ft
Comfrey needs ~975 GDD — county provides 2,340 GDD Excellent fit

Comfrey Planting Timeline โ€” Seneca County, OH

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors May 2 May 2 โ€“ May 16
Harvest July 4 Jul 4 โ€“ Sep 12

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

60โ€“90 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 5b

Growing Season

180 days

Growing Tips for Seneca 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

Level Up Your Garden

Frequently Asked Questions

When should I plant Comfrey in Seneca County, OH?

Seneca County is in Zone 5b with an average last frost of April 25. Plan your Comfrey planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Seneca County, OH?

Seneca County, Ohio is in USDA Hardiness Zone 5b. The average last spring frost is April 25 and first fall frost is October 22.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Seneca County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.

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Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Seneca County, OH. Local conditions may vary. Last updated: April 2026.