Allegheny County Soil Data
Allegheny County, Pennsylvania
Avg pH
5.1
Texture
Silt Loam
Drainage
N/A
Organic Matter
4.0%
Hydrologic Group
N/A
Data Story
About Soil in Allegheny County, Pennsylvania
Sharp acidity marks the Pittsburgh region
Allegheny County shows an average pH of 5.08, falling below the state average of 5.22 and well under the national median of 6.5. This high acidity often requires lime amendments for traditional garden vegetables to thrive. Taxonomic records are currently limited, but the chemical profile is typical of the Appalachian plateau.
Silty soils dominate the river valleys
The composition is 51.8% silt and 18.9% clay, providing a heavy texture that holds nutrients well. With only 19.8% sand, these soils can become compacted under heavy foot traffic or machinery. Gardeners should focus on adding organic material to improve the overall soil structure.
High water capacity despite low organic matter
Organic matter measures 3.97%, which is healthy by national standards but low compared to the state's 12.14% average. The available water capacity is strong at 0.166 in/in, outperforming the state average of 0.151 in/in. This ensures that crops have access to deep moisture even when the surface feels dry.
Slow drainage in silt-rich areas
While official drainage classes are not listed, the high silt and clay content often leads to slower percolation. This can be a challenge for building foundations and basement moisture management. Raised beds are a smart solution for backyard gardeners to prevent waterlogged roots.
Gardening in hardiness zone 6b
The county sits in hardiness zone 6b, allowing for a wide variety of perennials and hardy vegetables. Cool-season crops like kale and spinach thrive here, as do native berries that tolerate acidic conditions. Grab a trowel and start a patch of native perennials this weekend.
Soil Composition
Soil pH
Soil Series
Detailed soil series data not yet available for this county.
Hydrologic Group
Hydrologic group data not available.
Drainage Class
Drainage class data not available.
Soil Profile
Dominant texture: Silt Loam
Typical soil profile. Actual depths vary by location.
USDA Soil Orders
Frequently Asked Questions
What type of soil does Allegheny County have?
Allegheny County's soil is classified as Silt Loam. This indicates the relative proportions of sand, silt, and clay — 20% sand, 52% silt, and 19% clay. Loamy soils hold moisture well and support a wide range of plants.
Is Allegheny County's soil acidic or alkaline?
Allegheny County's soil has a low pH of 5.1, which is strongly acidic. Acidic soils benefit from lime applications to raise pH and improve nutrient availability.
What is the drainage class for Allegheny County?
Drainage class data is not currently available for Allegheny County.
What crops or plants grow well in Allegheny County's soil?
Based on Allegheny County's Silt Loam texture, pH of 5.1, and drainage class, the soil is well suited for acid-loving plants like blueberries and azaleas, row crops and vegetable gardens.
What USDA soil order is found in Allegheny County?
The dominant USDA soil order for Allegheny County is not currently available in our dataset.
Planning your lawn? View lawn care data for Allegheny County on LawnByCounty.com →
Other Counties in Pennsylvania
Soil data sourced from USDA SSURGO via Soil Data Access. Data is informational only and should not be used as a substitute for on-site soil testing. Contact your local NRCS office for site-specific soil information.