When to Plant Comfrey in Mercer 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.
Mercer County, North Dakota is in USDA Zone 4a. The average last spring frost is May 16 and the first fall frost is September 24, giving you a growing season of approximately 131 days.
At an elevation of 1,118 feet, Mercer County receives approximately 23 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Comfrey to ensure they mature before fall.
Mercer County Soil Profile
Soil Type
Loam
Soil pH
6.2-7.5
Drainage
Well Drained
Plant Planting Risk Windows
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
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Comfrey Planting Timeline — Mercer County, ND
Comfrey Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 23 | May 23 – Jun 6 |
| Harvest | July 25 | Jul 25 – Oct 3 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Transplant Outdoors |
| June | Transplant Outdoors |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
Sun
Partial Shade (3-6 hours)
Water
Moderate — regular watering
Days to Maturity
60–90 days
Soil pH
6 – 7
USDA Zone
Zone 4a
Growing Season
131 days
Growing Tips for Mercer 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
Comfrey in Other Locations
Frequently Asked Questions
When should I plant Comfrey in Mercer County, ND?
Mercer County is in Zone 4a with an average last frost of May 16. Plan your Comfrey planting based on this frost date — see the calendar above for exact timing.
What planting zone is Mercer County, ND?
Mercer County, North Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 16 and first fall frost is September 24.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Mercer County gardeners in Zone 4a organize planting dates, track what's growing, and never miss a planting window.
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