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When to Plant Comfrey in Sioux 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.

Sioux County, North Dakota is in USDA Zone 4a. The average last spring frost is May 12 and the first fall frost is October 1, giving you a growing season of approximately 142 days.

At an elevation of 1,012 feet, Sioux County receives approximately 32.3 inches of rainfall annually with predominantly loam soil. Summer highs average 82ยฐF, so choose short-season varieties of Comfrey to ensure they mature before fall.

Sioux County, ND (Zone 4a) Short season
142 days
Last Spring Frost May 12
142 growing days
First Fall Frost October 1

Sioux County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (2 days to spare)
Transplant: May 11 🍅 Harvest: Jul 13 – Sep 21
Recommended (50%) ✓ Fits season (2 days to spare)
Transplant: May 19 🍅 Harvest: Jul 21 – Sep 29
Safe Start (90%) ✓ Fits season (5 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
1.0″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 68 gal / 100 sq ft
Drought risk

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

Comfrey needs ~862 GDD — county provides 1,633 GDD Excellent fit

Comfrey Planting Timeline โ€” Sioux County, ND

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors May 19 May 19 โ€“ Jun 2
Harvest July 21 Jul 21 โ€“ Sep 29

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 4a

Growing Season

142 days

Growing Tips for Sioux 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 Sioux County, ND?

Sioux County is in Zone 4a with an average last frost of May 12. Plan your Comfrey planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Sioux County, ND?

Sioux County, North Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 12 and first fall frost is October 1.

๐ŸŒฑ

Plan Your Garden with Confidence

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