When to Plant Comfrey in Clearwater County, ID
Comfrey is a vigorous perennial herb valued as a dynamic accumulator of nutrients. Its leaves make excellent mulch, compost activator, and liquid fertilizer.
Clearwater County, Idaho is in USDA Zone 5b. The average last spring frost is May 17 and the first fall frost is September 28, giving you a growing season of approximately 134 days.
At an elevation of 7,800 feet, Clearwater County receives approximately 19 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, 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.
Clearwater County Soil Profile
Soil Type
Loam
Soil pH
6.5-8.1
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 — Clearwater County, ID
Comfrey Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 24 | May 24 – Jun 7 |
| Harvest | July 26 | Jul 26 – Oct 4 |
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 5b
Growing Season
134 days
Growing Tips for Clearwater 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 Clearwater County, ID?
Clearwater County is in Zone 5b with an average last frost of May 17. Plan your Comfrey planting based on this frost date — see the calendar above for exact timing.
What planting zone is Clearwater County, ID?
Clearwater County, Idaho is in USDA Hardiness Zone 5b. The average last spring frost is May 17 and first fall frost is September 28.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Clearwater County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.
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