Robertson County Soil Data
Robertson County, Texas
USDA SSURGO / PHZMAvg pH
6.5
Texture
Loam
Drainage
N/A
Organic Matter
1.4%
Hydrologic Group
D
Data Story
About Soil in Robertson County, Texas
Ideally Balanced Soil Acidity
Robertson County boasts a pH of 6.52, almost exactly matching the national median of 6.5. This rare balance makes it much less alkaline than the state average of 7.09, providing an ideal environment for nutrient uptake.
High Sand and Low Clay
The soil is composed of 51.9% sand and only 20.7% clay, leading to a light, workable texture. This high sand content ensures that the soil does not get too sticky or heavy during the rainy season.
Strong Score Despite Lower Organic Matter
While organic matter is 1.38% (below the state's 1.66%), the county's overall soil score of 42.1 is well above the state average of 28.8. The available water capacity of 0.134 in/in sits right at the state benchmark.
Drainage Challenges for Low Areas
Despite the sandy texture, the soil belongs to Hydrologic Group D, suggesting restrictive layers deeper down. Landowners should watch for slow drainage in low-lying areas during heavy rain events.
Prime Planting in Zone 9a
In hardiness zone 9a, the long summers are perfect for heat-loving crops like tomatoes and melons. The near-perfect pH means you can plant almost anything with very little soil amendment.
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
Drainage class data not available.
Soil Profile
Dominant texture: Loam
Typical soil profile. Actual depths vary by location.
USDA Soil Orders
Soil Amendment Products
Browse products to improve your soil health and lawn performance.
Browse Soil AmendmentsFrequently Asked Questions
What type of soil does Robertson County have?
Robertson County's soil is classified as Loam. This indicates the relative proportions of sand, silt, and clay — 52% sand, 26% silt, and 21% clay. Loamy soils hold moisture well and support a wide range of plants.
Is Robertson County's soil acidic or alkaline?
Robertson County's soil has a pH of 6.5, which is near neutral. This range is ideal for most garden plants and field crops.
What is the drainage class for Robertson County?
Drainage class data is not currently available for Robertson County.
What crops or plants grow well in Robertson County's soil?
Based on Robertson County's Loam texture, pH of 6.5, and drainage class, the soil is well suited for vegetables, grains, and most field crops, row crops and vegetable gardens.
What USDA soil order is found in Robertson County?
The dominant USDA soil order for Robertson County is not currently available in our dataset.
Soil & Planting Advisory: Robertson County
Soil Verdict
Robertson County is in USDA hardiness zone 9a, a warm climate zone. where winter lows can reach 20°F. Warm winters keep soil biology active nearly year-round, accelerating decomposition but increasing pest and disease pressure in topsoil.
Planting Guidance
Tropical and subtropical plants are viable. Year-round gardening is possible, though summer heat may limit some cool-season crops. Frost is rare; tender plants can overwinter with minimal protection. Always match plant selections to the specific microclimate of your property — low spots, slopes, and wind exposure can shift effective hardiness by half a zone.
Soil Implications
Rapid organic matter turnover means soils can become nutrient-poor quickly; test annually and fertilize based on results. High soil temperatures favor certain soilborne pathogens; practice crop rotation and avoid overwatering.
Regional Context
Robertson County is somewhat warmer than the Texas statewide average. The zone range of 8b-9a within the county means soil and planting decisions should account for local elevation and topography.
Planning your lawn? View lawn care data for Robertson 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.