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When to Plant Comfrey in Arlington County, VA

Arlington County, Virginia Zone 8a May

May in the garden — Arlington County, Virginia

Each item below is timed to Arlington County, Virginia's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 10
Avg. first frost October 31
Soil temp (4") 66°F
Watering Moderate
Pest pressure Moderate
Daylight 14.1 hrs
Looking ahead to June
  • First harvests: comfrey

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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.

Arlington County, Virginia is in USDA Zone 8a. The average last spring frost is April 10 and the first fall frost is October 31, giving you a growing season of approximately 204 days.

At an elevation of 284 feet, Arlington County receives approximately 46.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 92°F, providing good warmth for Comfrey during the growing season.

Arlington County, VA (Zone 8a) Long season
204 days
Last Spring Frost April 10
204 growing days
First Fall Frost October 31

Arlington County Soil Profile

Soil Type

Silt Loam

Soil pH

5.3-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (64 days to spare)
Transplant: Apr 8 🍅 Harvest: Jun 10 – Aug 19
Recommended (50%) ✓ Fits season (64 days to spare)
Transplant: Apr 17 🍅 Harvest: Jun 19 – Aug 28
Safe Start (90%) ✓ Fits season (64 days to spare)
Transplant: May 3 🍅 Harvest: Jul 5 – Sep 13

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 Arlington County

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

Soil pH

Your soil pH (5.3–6.8) overlaps with Comfrey's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.9%). Annual compost additions will help Comfrey.

How to Plant Comfrey

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

Succession Planting Comfrey

4
successive plantings in your 204-day season

Sow every 6.9 weeks. Last sowing by Aug 02 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 89 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 3.5" 0" ❄️ Dormant
Feb 3.8" 0" ❄️ Dormant
Mar 5" 0" ❄️ Dormant
Apr 4.3" 3.4" 0.9" 💧 Light watering
May 4.3" 3.3" 1" 💧 Light watering
Jun 4.3" 3.9" 0.4" 💧 Light watering
Jul 4.3" 4.5" 0" ✅ Rainfall sufficient
Aug 4.3" 4.9" 0" ✅ Rainfall sufficient
Sep 4.3" 4" 0.3" 💧 Light watering
Oct 4.3" 2.7" 1.6" 💧 Light watering
Nov 3.5" 0" ❄️ Dormant
Dec 3.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Arlington 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 ~1,425 GDD — county provides 3,876 GDD Excellent fit

Comfrey Planting Timeline — Arlington County, VA

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors April 17 Apr 17 – May 1
Harvest June 19 Jun 19 – Aug 28

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 8a

📆 Growing Season

204 days in Arlington County

Growing Tips for Comfrey in Arlington County

Direct sow Comfrey outdoors after April 10 in Arlington 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 Arlington County, VA?

Arlington County is in Zone 8a with an average last frost of April 10. Plan your Comfrey planting based on this frost date — see the calendar above for exact timing.

What planting zone is Arlington County, VA?

Arlington County, Virginia is in USDA Hardiness Zone 8a. The average last spring frost is April 10 and first fall frost is October 31.

🌱

Your Arlington County Garden Planner — Free

A 24-page printable planner built for Arlington County (Zone 8a). 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 Arlington County, VA. 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.