Soil series profile
Comfrey soil series
Comfrey is a poorly drained soil with a loam surface, mapped on 94,627 acres in 41 counties across 3 states. Hydrologic group B/D.
- Drainage class
- Poorly drained 89% of mapped acres
- Hydrologic group
- B/D >99% of mapped acres
- Typical topsoil pH
- 7.0 neutral · range 6.8–7.2
- Mapped area
- 95k acres in 41 counties, 3 states
Typical Comfrey profile
Texture and pH by depth
Show as a table
| Depth | Texture | pH | Clay | Sand | Organic matter |
|---|---|---|---|---|---|
| 0–7 in (H1) | Loam | 6.9 | 23% | 30% | 6% |
| 7–26 in (H2) | Loam | 6.9 | 27% | 30% | 3.5% |
| 26–37 in (H3) | Silty clay loam | 6.9 | 29% | 19% | 1.35% |
| 37–63 in (H4) | Loam | 7.0 | 25% | 35% | 1% |

What this means
What Comfrey soil means for gardens, lawns and septic systems
For gardens
Typical topsoil in Comfrey soils is neutral: pH 7.0 (most land between 6.8 and 7.2), the range most vegetables, flowers and lawn grasses prefer.
Loamy topsoil (loam, silt loam and similar) covers >99% of mapped Comfrey acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is loam (60% of mapped Comfrey acres).
>99% of mapped Comfrey acres is somewhat poorly to very poorly drained, so soil stays soggy for long spells after rain and in wet seasons. Raised beds, plants that tolerate wet feet, and not working the soil while wet all help.
For lawns and yards
On >99% of mapped acres, rain soaks in slowly (hydrologic groups C and D, including dual groups that are D until drained). Expect runoff and puddles after heavy rain: core-aerate compacted lawns and keep ground sloping away from foundations.
A seasonal high water table comes within 18 inches of the surface on >99% of mapped acres, often in spring. Basements, sump pumps and lawns in low spots feel it first.
For a septic system
For conventional septic absorption fields, NRCS rates >99% of the acres in mapped Comfrey soils very limited, 0% somewhat limited and 0% not limited.
Where the soil is very limited (slow permeability, a high water table, flooding, shallow bedrock or steep slopes), alternative systems such as mound or sand-filter designs are common and cost more.
Flooding is mapped on >99% of the acres (36% occasional, 63% frequent).
Only a licensed site evaluation or perc test at the actual lot decides whether a system is allowed and which design.
Where Comfrey soil is found
Mapped acres
Comfrey is mapped in Illinois, Minnesota and Indiana.
| County | Acres | Share of county land |
|---|---|---|
| Winnebago County, IL | 16,262 | 5.2% |
| Ogle County, IL | 9,878 | 2.1% |
| Blue Earth County, MN | 8,122 | 1.7% |
| Lee County, IL | 7,750 | 1.7% |
| McHenry County, IL | 7,544 | 2.1% |
| Houston County, MN | 7,368 | 2.1% |
| Benton County, IN | 5,827 | 2.3% |
| Nobles County, MN | 5,081 | 1.1% |
| Boone County, IL | 3,989 | 2.3% |
| Livingston County, IL | 3,546 | 0.5% |
| Warren County, IN | 3,310 | 1.5% |
| Iroquois County, IL | 2,956 | 0.4% |
| Winona County, MN | 2,229 | 0.6% |
| Cass County, IL | 2,078 | 0.9% |
| Rock County, MN | 1,698 | 0.5% |
| Grundy County, IL | 1,561 | 0.6% |
| Scott County, MN | 1,453 | 0.6% |
| Newton County, IN | 940 | 0.4% |
| Cumberland County, IL | 668 | 0.3% |
| LaSalle County, IL | 458 | 0.1% |
| Redwood County, MN | 354 | 0.1% |
| Stephenson County, IL | 330 | 0.1% |
| DeKalb County, IL | 308 | 0.1% |
| Whiteside County, IL | 205 | 0.0% |
| Olmsted County, MN | 191 | 0.0% |
| Kane County, IL | 114 | 0.0% |
| Jo Daviess County, IL | 97 | 0.0% |
| Kendall County, IL | 81 | 0.0% |
| Wabasha County, MN | 62 | 0.0% |
| Carroll County, IL | 45 | 0.0% |
| Cottonwood County, MN | 39 | 0.0% |
| Will County, IL | 27 | 0.0% |
| Bureau County, IL | 11 | 0.0% |
| Murray County, MN | 10 | 0.0% |
| Tazewell County, IL | 10 | 0.0% |
| Logan County, IL | 8 | 0.0% |
| Kankakee County, IL | 7 | 0.0% |
| Brown County, IL | 5 | 0.0% |
| Peoria County, IL | 4 | 0.0% |
| Lake County, IL | 2 | 0.0% |
| Lyon County, MN | 1 | 0.0% |
Septic absorption fields
NRCS rating, share of Comfrey acres
Show as a table
| Category | Share of acres |
|---|---|
| Not limited | 0.0% |
| Somewhat limited | 0.0% |
| Very limited | 99.1% |
| Not rated | 0.9% |
Drainage, water table and flooding
Share of Comfrey acres
- Depth to seasonal high water table
- About 6 inches (median where reported); within 18 inches on >99% of acres.
- Flooding
- Mapped as flooding on >99% of acres (36% occasional, 63% frequent).
- Slope
- Typically 0–1% (median 0%).
- Topsoil organic matter
- Median 6%.
Drainage class
Show as a table
| Category | Share of acres |
|---|---|
| Excessively drained | 0.0% |
| Somewhat excessively drained | 0.0% |
| Well drained | 0.0% |
| Moderately well drained | 0.0% |
| Somewhat poorly drained | 0.0% |
| Poorly drained | 88.9% |
| Very poorly drained | 10.8% |
| Not rated | 0.4% |
Hydrologic soil group
Show as a table
| Category | Share of acres |
|---|---|
| A: fast infiltration (mostly sandy or gravelly) | 0.0% |
| B: moderate infiltration | 0.0% |
| C: slow infiltration | 0.0% |
| D: very slow infiltration (clayey, shallow or wet) | 0.0% |
| A/D: D as is, A if drained | 0.0% |
| B/D: D as is, B if drained | 99.1% |
| C/D: D as is, C if drained | 0.0% |
| Not rated | 0.9% |
Sources & data dates
- Source
- USDA NRCS Soil Survey Geographic Database (SSURGO), queried through Soil Data Access. Public domain.
- Data date
- SSURGO as published on November 3, 2026 (most recent survey area update October 26, 2026). NRCS refreshes SSURGO each October.
- Scope
- All map unit components named Comfrey (component kind "Series") in SSURGO: 94,627 acres.
- Method
- Shares are by mapped acres of Comfrey components. The profile comes from the single largest Comfrey component. Full methodology.