Blog

When to Plant Comfrey in Platte 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.

Platte County, Missouri is in USDA Zone 6a. The average last spring frost is April 10 and the first fall frost is October 26, giving you a growing season of approximately 199 days.

At an elevation of 1,021 feet, Platte County receives approximately 35.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86ยฐF, providing good warmth for Comfrey during the growing season.

Platte County, MO (Zone 6a) Moderate season
199 days
Last Spring Frost April 10
199 growing days
First Fall Frost October 26

Platte County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (58 days to spare)
Transplant: Apr 10 🍅 Harvest: Jun 12 – Aug 21
Recommended (50%) ✓ Fits season (59 days to spare)
Transplant: Apr 17 🍅 Harvest: Jun 19 – Aug 28
Safe Start (90%) ✓ Fits season (63 days to spare)
Transplant: May 2 🍅 Harvest: Jul 4 – Sep 12

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
0.3″/week
Watering frequency Only during dry spells
Season total 437 gal / 100 sq ft
Comfrey needs ~1,088 GDD — county provides 2,885 GDD Excellent fit

Comfrey Planting Timeline โ€” Platte County, MO

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

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

199 days

Growing Tips for Platte 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 Platte County, MO?

Platte County is in Zone 6a 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 Platte County, MO?

Platte County, Missouri is in USDA Hardiness Zone 6a. The average last spring frost is April 10 and first fall frost is October 26.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Platte County gardeners in Zone 6a 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 Platte County, MO. Local conditions may vary. Last updated: April 2026.