When to plant Comfrey in Carlton County, MN
Plant Comfrey in Carlton County, between May 19 and June 2 — the only viable window. Zone 4a's short season (143 frost-free days) rules out a fall crop.
When to Plant Comfrey in Carlton County, MN
Comfrey is a vigorous perennial herb valued as a dynamic accumulator of nutrients. Its leaves make excellent mulch, compost activator, and liquid fertilizer.
Carlton County, Minnesota is in USDA Zone 4a. The average last spring frost is May 12 and the first fall frost is October 2, giving you a growing season of approximately 143 days.
At an elevation of 516 feet, Carlton County receives approximately 32.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82°F, so choose short-season varieties of Comfrey to ensure they mature before fall.
Carlton County Soil Profile
Soil Type
Silt Loam
Soil pH
6.2-7.1
Drainage
Well Drained
Monthly Watering Guide for Comfrey
Comfrey needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Comfrey Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.5" | 0" | ❄️ Dormant |
| Mar | — | 2.5" | 0" | ❄️ Dormant |
| Apr | — | 3.1" | 0" | ❄️ Dormant |
| May | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Jun | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Jul | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Aug | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Sep | 4.3" | 2.7" | 1.6" | 💧 Light watering |
| Oct | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| Nov | — | 2.5" | 0" | ❄️ Dormant |
| Dec | — | 1.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Carlton County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Comfrey Planting Timeline — Carlton County, MN
Comfrey Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 19 | May 19 – Jun 2 |
| Harvest | July 21 | Jul 21 – Sep 29 |
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 | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
Moderate — regular watering
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–7 · Your soil: N/A
🗺️ USDA Zone
Zone 4a
📆 Growing Season
143 days in Carlton County
Growing Tips for Carlton 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
Check more plant combinations with our Companion Planting Checker →
Comfrey in Other Locations
Frequently Asked Questions
When should I plant Comfrey in Carlton County, MN?
Carlton County is in Zone 4a with an average last frost of May 12. Plan your Comfrey planting based on this frost date — see the calendar above for exact timing.
What planting zone is Carlton County, MN?
Carlton County, Minnesota is in USDA Hardiness Zone 4a. The average last spring frost is May 12 and first fall frost is October 2.
When should I plant Comfrey in Carlton County, MN?
In Carlton County, MN, plant Comfrey after the last frost (around May 12) and before the first frost (around October 2). Best results when soil holds above 50°F.
What growing zone is Carlton County, MN for Comfrey?
Carlton County sits in USDA Zone 4a. Comfrey grows reliably in zones 3a through 9b, so it's a good fit here.
Can Comfrey grow in Carlton County's climate?
Yes — Comfrey grows well in Carlton County's temperate climate. Carlton County averages a 143-day frost-free season, with last frost around May 12 and first frost around October 2.
Your Carlton County Garden Planner — Free
A 22-page printable planner built for Carlton County (Zone 4a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.