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When to Plant Comfrey in Delaware 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.

Delaware County, Pennsylvania is in USDA Zone 7a. The average last spring frost is April 16 and the first fall frost is October 24, giving you a growing season of approximately 191 days.

At an elevation of 1,094 feet, Delaware County receives approximately 38.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89ยฐF, providing good warmth for Comfrey during the growing season.

Delaware County, PA (Zone 7a) Moderate season
191 days
Last Spring Frost April 16
191 growing days
First Fall Frost October 24

Delaware County Soil Profile

Soil Type

Silt Loam

Soil pH

5-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (48 days to spare)
Transplant: Apr 20 🍅 Harvest: Jun 22 – Aug 31
Recommended (50%) ✓ Fits season (51 days to spare)
Transplant: Apr 23 🍅 Harvest: Jun 25 – Sep 3
Safe Start (90%) ✓ Fits season (37 days to spare)
Transplant: May 18 🍅 Harvest: Jul 20 – Sep 28

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
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 268 gal / 100 sq ft
Comfrey needs ~1,256 GDD — county provides 3,199 GDD Excellent fit

Comfrey Planting Timeline โ€” Delaware County, PA

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors April 23 Apr 23 โ€“ May 7
Harvest June 25 Jun 25 โ€“ Sep 3

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Transplant Outdoors
May Transplant Outdoors
June Harvest
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 7a

Growing Season

191 days

Growing Tips for Delaware 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 Delaware County, PA?

Delaware County is in Zone 7a with an average last frost of April 16. Plan your Comfrey planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Delaware County, PA?

Delaware County, Pennsylvania is in USDA Hardiness Zone 7a. The average last spring frost is April 16 and first fall frost is October 24.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Delaware County gardeners in Zone 7a 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 Delaware County, PA. Local conditions may vary. Last updated: April 2026.