Blog

When to Plant Comfrey in Baltimore City, MD

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

Baltimore City, Maryland is in USDA Zone 7a. The average last spring frost is April 3 and the first fall frost is November 6, giving you a growing season of approximately 217 days.

At an elevation of 213 feet, Baltimore City receives approximately 48.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 94ยฐF, providing good warmth for Comfrey during the growing season.

Baltimore City, MD (Zone 7a) Long season
217 days
Last Spring Frost April 3
217 growing days
First Fall Frost November 6

Baltimore City Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (78 days to spare)
Transplant: Apr 4 🍅 Harvest: Jun 6 – Aug 15
Recommended (50%) ✓ Fits season (77 days to spare)
Transplant: Apr 10 🍅 Harvest: Jun 12 – Aug 21
Safe Start (90%) ✓ Fits season (79 days to spare)
Transplant: Apr 23 🍅 Harvest: Jun 25 – Sep 3

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
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Comfrey needs ~1,538 GDD — county provides 4,448 GDD Excellent fit

Comfrey Planting Timeline โ€” Baltimore City, MD

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors April 10 Apr 10 โ€“ Apr 24
Harvest June 12 Jun 12 โ€“ Aug 21

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 โ€”
June Harvest
July Harvest
August Harvest
September โ€”
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

217 days

Growing Tips for Baltimore City

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 Baltimore City, MD?

Baltimore City is in Zone 7a with an average last frost of April 3. Plan your Comfrey planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Baltimore City, MD?

Baltimore City, Maryland is in USDA Hardiness Zone 7a. The average last spring frost is April 3 and first fall frost is November 6.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Baltimore City gardeners in Zone 7a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

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 Baltimore City, MD. Local conditions may vary. Last updated: April 2026.