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When to Plant Comfrey in Smith County, TN

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

Smith County, Tennessee is in USDA Zone 7a. The average last spring frost is April 10 and the first fall frost is October 28, giving you a growing season of approximately 201 days.

At an elevation of 3,829 feet, Smith County receives approximately 41.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 94ยฐF, providing good warmth for Comfrey during the growing season.

Smith County, TN (Zone 7a) Long season
201 days
Last Spring Frost April 10
201 growing days
First Fall Frost October 28

Smith County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (59 days to spare)
Transplant: Apr 12 🍅 Harvest: Jun 14 – Aug 23
Recommended (50%) ✓ Fits season (61 days to spare)
Transplant: Apr 17 🍅 Harvest: Jun 19 – Aug 28
Safe Start (90%) ✓ Fits season (63 days to spare)
Transplant: Apr 28 🍅 Harvest: Jun 30 – Sep 8

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 Smith County

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

Soil pH

Your soil pH (5.5โ€“7.0) overlaps with Comfrey's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

The silt loam soil in Smith County is excellent for Comfrey โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Comfrey.

How to Plant Comfrey

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

Succession Planting Comfrey

3
successive plantings in your 201-day season

Sow every 6.9 weeks. Last sowing by Jul 30 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 245 gal / 100 sq ft
Comfrey needs ~1,538 GDD — county provides 4,120 GDD Excellent fit

Comfrey Planting Timeline โ€” Smith County, TN

Comfrey Planting Calendar

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

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 โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Partial Shade (3-6 hours)

๐Ÿ’ง Water

1"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

60โ€“90 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 7a

๐Ÿ“† Growing Season

201 days in Smith County

Growing Tips for Comfrey in Smith County

Direct sow Comfrey outdoors after April 10 in Smith 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

Level Up Your Garden

Frequently Asked Questions

When should I plant Comfrey in Smith County, TN?

Smith County is in Zone 7a with an average last frost of April 10. Plan your Comfrey planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Smith County, TN?

Smith County, Tennessee is in USDA Hardiness Zone 7a. The average last spring frost is April 10 and first fall frost is October 28.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Smith County 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 Smith County, TN. Local conditions may vary. Last updated: April 2026.