St. Tammany Parish Soil Data
St. Tammany Parish, Louisiana
Avg pH
4.8
Texture
Loam
Drainage
Very poorly drained
Organic Matter
15.4%
Hydrologic Group
D
Data Story
About Soil in St. Tammany Parish, Louisiana
The Acidic Entisols of St. Tammany
The average pH here is quite low at 4.75, making it significantly more acidic than the state average of 5.74. These soils are classified as Entisols, which are geologically young and chemically distinct.
A Gritty and Varied Mix
With 32.4% sand and 29.5% silt, these soils have more grit than many of their coastal neighbors. However, the 18.1% clay helps provide enough structure to keep the soil from being overly loose.
Rich Organic Matter and High Capacity
Organic matter is very high at 15.39%, more than double the state average. This helps support an available water capacity of 0.211 in/in, ensuring that plants have access to water even in the sandy patches.
Navigating Very Poorly Drained Lands
The soil is classified as very poorly drained and falls into hydrologic group D. This means water tends to sit on the surface, requiring elevated beds for gardening and specialized foundations for building.
Blueberries Love the Acidic Zone 9a
The acidic 4.75 pH is perfect for acid-loving plants like blueberries and azaleas. Don't let the drainage stop you; with a 63.6 soil score and some raised beds, your landscape will flourish.
Soil Composition
Soil pH
Soil Series
Detailed soil series data not yet available for this county.
Hydrologic Group
Group D — High Runoff
Clay soils with very slow infiltration rates. Highest runoff potential. These soils have a permanent high water table or are shallow over impervious material.
Drainage Class
Very poorly drained
Water is removed so slowly that free water remains at or on the surface most of the year. Typically wetland soils.
Soil Profile
Dominant texture: Loam
Typical soil profile. Actual depths vary by location.
USDA Soil Orders
Frequently Asked Questions
What type of soil does St. Tammany Parish have?
St. Tammany Parish's soil is classified as Loam. This indicates the relative proportions of sand, silt, and clay — 32% sand, 29% silt, and 18% clay. Loamy soils hold moisture well and support a wide range of plants.
Is St. Tammany Parish's soil acidic or alkaline?
St. Tammany Parish's soil has a low pH of 4.8, which is strongly acidic. Acidic soils benefit from lime applications to raise pH and improve nutrient availability.
What is the drainage class for St. Tammany Parish?
St. Tammany Parish has a dominant drainage class of "Very poorly drained." Poorly drained soils retain water for extended periods, which can limit crop choices and may require tile drainage or raised beds.
What crops or plants grow well in St. Tammany Parish's soil?
Based on St. Tammany Parish's Loam texture, pH of 4.8, and Very poorly drained, the soil is well suited for acid-loving plants like blueberries and azaleas, row crops and vegetable gardens, rice, cranberries, and other water-tolerant species.
What USDA soil order is found in St. Tammany Parish?
St. Tammany Parish's dominant soil order is Entisols. Entisols are recently formed soils with little to no horizon development. They are common on floodplains, steep slopes, and sandy deposits.
Planning your lawn? View lawn care data for St. Tammany Parish on LawnByCounty.com →
Other Counties in Louisiana
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.