Soil series profile

Sproulish soil series

Sproulish is a well drained soil with a gravelly silt loam surface, mapped on 163,248 acres in 2 counties in CA. Hydrologic group C.

#2249 by mapped area fine-loamy Typic Dystrustepts (Inceptisols)

Drainage class: Well drained
Hydrologic group: C
Typical topsoil pH: 5.8
Mapped area: 163k

Typical Sproulish profile

Texture and pH by depth

Depth to scale. More strongly shaded layers hold more clay. Horizon names are the soil survey's (A = topsoil, B = subsoil, C = parent material).

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Typical Sproulish horizons (representative values)
Depth	Texture	pH	Clay	Sand	Organic matter
0–2 in (Oi)	Slightly decomposed plant material	6.0	15%	35%	75%
2–6 in (A)	Gravelly silt loam	5.8	26%	20%	5%
6–13 in (Bt1)	Paragravelly clay loam	5.6	30%	34%	2%
13–21 in (Bt2)	Gravelly loam	5.6	26%	38%	2%
21–47 in (Bt3)	Clay loam	5.2	29%	34%	0.5%
47–63 in (Bt4)	Paragravelly silty clay loam	5.2	33%	18%	0.5%
63–79 in (Bt5)	Paragravelly silty clay loam	5.2	36%	19%	0.5%

Representative values from the most extensive Sproulish map unit (Sproulish-Canoecreek-Redwohly complex, 30 to 50 percent slopes, survey area CA601). Other map units of this series vary within the series range.

Stock photo for illustration, not a sample of this soil series. Credit on the Sources & method page.

What this means

What Sproulish soil means for gardens, lawns and septic systems

For gardens

Typical topsoil in Sproulish soils is moderately acidic: pH 5.8 (most land between 5.8 and 6.5). Many vegetables grow well here, and some gardens benefit from a little lime. Test before adding any.

Loamy topsoil (loam, silt loam and similar) covers 100% of mapped Sproulish acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is gravelly loam (35% of mapped Sproulish acres).

100% of mapped Sproulish acres is moderately well to excessively drained, which suits most garden plants.

For lawns and yards

On 73% 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.

For a septic system

For conventional septic absorption fields, NRCS rates 100% of the acres in mapped Sproulish 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.

Only a licensed site evaluation or perc test at the actual lot decides whether a system is allowed and which design.

Generated from the mapped numbers above using fixed rules, not a site visit. See how these notes are written.

Where Sproulish soil is found

Mapped acres

Sproulish is mapped in California.

Counties with the most mapped Sproulish soil
County	Acres	Share of county land
Humboldt County, CA	158,666	7.8%
Mendocino County, CA	4,583	0.2%

Septic absorption fields

NRCS rating, share of Sproulish acres

Not limited 0%

Somewhat limited 0%

Very limited 100%

Septic tank absorption field rating across mapped Sproulish acres. Scale 0 to 100% of mapped land.

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Septic tank absorption field rating across mapped Sproulish acres.
Category	Share of acres
Not limited	0.0%
Somewhat limited	0.0%
Very limited	100.0%

Drainage, water table and flooding

Share of Sproulish acres

Depth to seasonal high water table: None reported within about 6.5 feet (median where reported).
Flooding: Not mapped as flooding on most acres.
Slope: Typically 25–65% (median 40%).
Topsoil organic matter: Median 5%.

Drainage class

Excessively drained 0%

Somewhat excessively drained 0%

Well drained 100%

Moderately well drained 0%

Somewhat poorly drained 0%

Poorly drained 0%

Very poorly drained 0%

Drainage class across mapped Sproulish acres. Scale 0 to 100% of mapped land.

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Drainage class across mapped Sproulish acres.
Category	Share of acres
Excessively drained	0.0%
Somewhat excessively drained	0.0%
Well drained	100.0%
Moderately well drained	0.0%
Somewhat poorly drained	0.0%
Poorly drained	0.0%
Very poorly drained	0.0%

Hydrologic soil group

A: fast infiltration (mostly sandy or gravelly) 0%

B: moderate infiltration 27%

C: slow infiltration 73%

D: very slow infiltration (clayey, shallow or wet) 0%

A/D: D as is, A if drained 0%

B/D: D as is, B if drained 0%

C/D: D as is, C if drained 0%

Hydrologic soil group across mapped Sproulish acres. Scale 0 to 100% of mapped land.

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Hydrologic soil group across mapped Sproulish acres.
Category	Share of acres
A: fast infiltration (mostly sandy or gravelly)	0.0%
B: moderate infiltration	26.6%
C: slow infiltration	73.4%
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	0.0%
C/D: D as is, C if drained	0.0%

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 Sproulish (component kind "Series") in SSURGO: 163,248 acres.
Method: Shares are by mapped acres of Sproulish components. The profile comes from the single largest Sproulish component. Full methodology.

Independent reference site. No government affiliation or endorsement.

Full narrative description: USDA Official Soil Series Description for Sproulish.