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When to Plant Comfrey in Pembina 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.

Pembina County, North Dakota is in USDA Zone 3b. The average last spring frost is May 15 and the first fall frost is September 28, giving you a growing season of approximately 136 days.

At an elevation of 958 feet, Pembina County receives approximately 26.5 inches of rainfall annually with predominantly loam soil. Summer highs average 79ยฐF, so choose short-season varieties of Comfrey to ensure they mature before fall.

Pembina County, ND (Zone 3b) Short season
136 days
Last Spring Frost May 15
136 growing days
First Fall Frost September 28

Pembina County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (1 days to spare)
Transplant: May 18 🍅 Harvest: Jul 20 – Sep 21
Recommended (50%) ✓ Fits season (3 days to spare)
Transplant: May 22 🍅 Harvest: Jul 24 – Sep 25
Safe Start (90%) ✓ Fits season (2 days to spare)
Transplant: Jun 6 🍅 Harvest: Aug 8 – Oct 10

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 220 gal / 100 sq ft
Comfrey needs ~694 GDD — county provides 1,258 GDD Excellent fit

Comfrey Planting Timeline โ€” Pembina County, ND

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors May 22 May 22 โ€“ Jun 5
Harvest July 24 Jul 24 โ€“ Sep 25

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 Transplant Outdoors
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 3b

Growing Season

136 days

Growing Tips for Pembina 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 Pembina County, ND?

Pembina County is in Zone 3b with an average last frost of May 15. Plan your Comfrey planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Pembina County, ND?

Pembina County, North Dakota is in USDA Hardiness Zone 3b. The average last spring frost is May 15 and first fall frost is September 28.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Pembina County gardeners in Zone 3b 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 Pembina County, ND. Local conditions may vary. Last updated: April 2026.