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When to Plant Comfrey in Lake County, MT

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

Lake County, Montana is in USDA Zone 5a. The average last spring frost is May 31 and the first fall frost is September 12, giving you a growing season of approximately 104 days.

At an elevation of 6,938 feet, Lake County receives approximately 12.8 inches of rainfall annually with predominantly loam soil. Summer highs average 85ยฐF, providing good warmth for Comfrey during the growing season. With low rainfall, drip irrigation is essential for growing Comfrey successfully. Mulch heavily to conserve soil moisture.

Lake County, MT (Zone 5a) Short season
104 days
Last Spring Frost May 31
104 growing days
First Fall Frost September 12

Lake County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 27 🍅 Harvest: Jul 29 – Oct 7
Recommended (50%) ✗ May not fit
Transplant: Jun 7 🍅 Harvest: Aug 9 – Oct 18
Safe Start (90%) ✗ May not fit
Transplant: Jun 28 🍅 Harvest: Aug 30 – Nov 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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 537 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” consider drought-tolerant varieties and mulching

Comfrey needs ~1,031 GDD — county provides 1,430 GDD Excellent fit

Comfrey Planting Timeline โ€” Lake County, MT

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors June 7 Jun 7 โ€“ Jun 21
Harvest August 9 Aug 9 โ€“ Oct 18

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May โ€”
June Transplant Outdoors
July โ€”
August Harvest
September Harvest
October Harvest
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 5a

Growing Season

104 days

Growing Tips for Lake 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 Lake County, MT?

Lake County is in Zone 5a with an average last frost of May 31. Plan your Comfrey planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Lake County, MT?

Lake County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is May 31 and first fall frost is September 12.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Lake County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

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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 Lake County, MT. Local conditions may vary. Last updated: April 2026.