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When to Plant Comfrey in Barnes County, ND

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

Barnes County, North Dakota is in USDA Zone 4a. The average last spring frost is May 9 and the first fall frost is September 29, giving you a growing season of approximately 143 days.

At an elevation of 623 feet, Barnes County receives approximately 20.5 inches of rainfall annually with predominantly loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Comfrey to ensure they mature before fall.

Barnes County, ND (Zone 4a) Short season
143 days
Last Spring Frost May 9
143 growing days
First Fall Frost September 29

Barnes County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (6 days to spare)
Transplant: May 8 🍅 Harvest: Jul 10 – Sep 18
Recommended (50%) ✓ Fits season (3 days to spare)
Transplant: May 16 🍅 Harvest: Jul 18 – Sep 26
Safe Start (90%) ✓ Fits season (9 days to spare)
Transplant: May 26 🍅 Harvest: Jul 28 – Oct 6

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
0.6″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 506 gal / 100 sq ft
Comfrey needs ~975 GDD — county provides 1,859 GDD Excellent fit

Comfrey Planting Timeline โ€” Barnes County, ND

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors May 16 May 16 โ€“ May 30
Harvest July 18 Jul 18 โ€“ Sep 26

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 Transplant Outdoors
June โ€”
July Harvest
August Harvest
September Harvest
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 4a

Growing Season

143 days

Growing Tips for Barnes 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 Barnes County, ND?

Barnes County is in Zone 4a with an average last frost of May 9. Plan your Comfrey planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Barnes County, ND?

Barnes County, North Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 9 and first fall frost is September 29.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Barnes County gardeners in Zone 4a 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 Barnes County, ND. Local conditions may vary. Last updated: April 2026.