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When to Plant Comfrey in Osage County, MO

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

Osage County, Missouri is in USDA Zone 6a. The average last spring frost is April 6 and the first fall frost is October 30, giving you a growing season of approximately 207 days.

At an elevation of 1,300 feet, Osage County receives approximately 38.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90ยฐF, providing good warmth for Comfrey during the growing season.

Osage County, MO (Zone 6a) Long season
207 days
Last Spring Frost April 6
207 growing days
First Fall Frost October 30

Osage County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (71 days to spare)
Transplant: Apr 4 🍅 Harvest: Jun 6 – Aug 15
Recommended (50%) ✓ Fits season (67 days to spare)
Transplant: Apr 13 🍅 Harvest: Jun 15 – Aug 24
Safe Start (90%) ✓ Fits season (71 days to spare)
Transplant: Apr 25 🍅 Harvest: Jun 27 – Sep 5

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 396 gal / 100 sq ft
Comfrey needs ~1,312 GDD — county provides 3,622 GDD Excellent fit

Comfrey Planting Timeline โ€” Osage County, MO

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors April 13 Apr 13 โ€“ Apr 27
Harvest June 15 Jun 15 โ€“ Aug 24

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 6a

Growing Season

207 days

Growing Tips for Osage 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 Osage County, MO?

Osage County is in Zone 6a with an average last frost of April 6. Plan your Comfrey planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Osage County, MO?

Osage County, Missouri is in USDA Hardiness Zone 6a. The average last spring frost is April 6 and first fall frost is October 30.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Osage County gardeners in Zone 6a organize planting dates, track what's growing, and never miss a planting window.

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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 Osage County, MO. Local conditions may vary. Last updated: April 2026.