Soil types in Pennsylvania

What this means

What Pennsylvania soils mean for gardens, lawns and septic systems

For gardens

Typical topsoil in Pennsylvania is strongly acidic: pH 5.3 (most land between 4.6 and 6.2). Most vegetables and lawn grasses do best around 6.0 to 7.0, so lime is often needed; blueberries, azaleas and rhododendrons like it as it is.

Loamy topsoil (loam, silt loam and similar) covers 96% of the land: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is silt loam (31% of the land).

80% of the land is moderately well to excessively drained, which suits most garden plants.

For lawns and yards

On 60% of the land, 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 26% of the land, often in spring. Basements, sump pumps and lawns in low spots feel it first.

For septic systems

For conventional septic absorption fields, NRCS rates 91% of the land in Pennsylvania very limited, 6% somewhat limited and <1% not limited (2% not rated, such as urban land, pits or water).

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 5% of the land (2% occasional, 3% frequent).

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.