Starr County Soil Data
Starr County, Texas
Avg pH
7.8
Texture
Silt loam
Drainage
Well drained
Organic Matter
1.1%
Hydrologic Group
B
Data Story
About Soil in Starr County, Texas
Silty Entisols of the Rio Grande
Starr County is dominated by Entisols, which are young soils with an alkaline pH of 7.78. This is notably higher than the state average of 7.09 and the national median of 6.5. These soils are often found in floodplains or areas where recent sediment deposition has occurred.
The Smooth Feel of Silt Loam
The dominant texture is silt loam, created by a balanced mix of 35.7% silt and 36.4% sand. With 24.2% clay, the soil offers a smooth workability that retains moisture better than pure sand. This composition provides an excellent physical environment for root development in agricultural settings.
Reliable Water Storage Capability
The soil provides an available water capacity of 0.138 in/in, which sits slightly above the Texas state average. However, organic matter is low at 1.09%, which is typical for arid South Texas environments. Improving carbon levels through cover cropping could significantly boost the natural fertility of these Entisols.
Well Drained and Ready for Use
Classified as well-drained and belonging to Hydrologic Group B, these soils allow for moderate infiltration when wet. This makes them ideal for various uses, from vegetable farming to residential development. The soil effectively manages moderate rainfall without frequent surface ponding.
Sun-Drenched Success in Zone 9b
Starr County sits in the subtropical Zone 9b, where citrus, melons, and onions thrive in the silt loam. The long, hot growing season is perfect for heat-loving tropicals and traditional South Texas row crops. Start a garden today and take advantage of some of the best-drained soil in the region.
Soil Composition
Soil pH
Soil Series
Detailed soil series data not yet available for this county.
Hydrologic Group
Group B — Moderate Runoff
Moderately deep, moderately well-drained soils with moderate infiltration rates. Good balance of drainage and water retention.
Drainage Class
Well drained
Water is removed from the soil readily but not rapidly. Optimal for most plants and construction.
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 Starr County have?
Starr County's soil is classified as Silt loam. This indicates the relative proportions of sand, silt, and clay — 36% sand, 36% silt, and 24% clay. Loamy soils hold moisture well and support a wide range of plants.
Is Starr County's soil acidic or alkaline?
Starr County's soil has a pH of 7.8, which is mildly to moderately alkaline. Sulfur amendments can lower pH if needed.
What is the drainage class for Starr County?
Starr County has a dominant drainage class of "Well drained." Well-drained soils allow excess water to move through quickly, reducing waterlogging risk and supporting most field and garden crops.
What crops or plants grow well in Starr County's soil?
Based on Starr County's Silt loam texture, pH of 7.8, and Well drained, the soil is well suited for drought-tolerant crops and native grasses, row crops and vegetable gardens, most annual and perennial crops.
What USDA soil order is found in Starr County?
Starr County'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 Starr County on LawnByCounty.com →
Other Counties in Texas
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.