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When to Plant Comfrey in Warren County, PA

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

Warren County, Pennsylvania is in USDA Zone 5a. The average last spring frost is May 13 and the first fall frost is October 13, giving you a growing season of approximately 153 days.

At an elevation of 1,158 feet, Warren County receives approximately 43.3 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.

Warren County, PA (Zone 5a) Moderate season
153 days
Last Spring Frost May 13
153 growing days
First Fall Frost October 13

Warren County Soil Profile

Soil Type

Silt Loam

Soil pH

5.1-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (15 days to spare)
Transplant: May 12 🍅 Harvest: Jul 14 – Sep 22
Recommended (50%) ✓ Fits season (13 days to spare)
Transplant: May 20 🍅 Harvest: Jul 22 – Sep 30
Safe Start (90%) ✓ Fits season (8 days to spare)
Transplant: Jun 8 🍅 Harvest: Aug 10 – Oct 19

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
1.2″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Comfrey needs ~975 GDD — county provides 1,989 GDD Excellent fit

Comfrey Planting Timeline โ€” Warren County, PA

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors May 20 May 20 โ€“ Jun 3
Harvest July 22 Jul 22 โ€“ Sep 30

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 Transplant Outdoors
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 5a

Growing Season

153 days

Growing Tips for Warren 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 Warren County, PA?

Warren County is in Zone 5a with an average last frost of May 13. Plan your Comfrey planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Warren County, PA?

Warren County, Pennsylvania is in USDA Hardiness Zone 5a. The average last spring frost is May 13 and first fall frost is October 13.

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Plan Your Garden with Confidence

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

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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 Warren County, PA. Local conditions may vary. Last updated: April 2026.