Robertson County Soil Data
Robertson County, Tennessee
USDA SSURGO / PHZMAvg pH
5.6
Texture
Gravelly silt loam
Drainage
Well drained
Organic Matter
1.9%
Hydrologic Group
B
Data Story
About Soil in Robertson County, Tennessee
Rich Alfisols of Robertson County
Robertson County is dominated by Alfisols, characterized by their natural fertility and an average pH of 5.60. This pH is more alkaline than the Tennessee average of 5.35, though it remains below the national median of 6.5.
The strength of gravelly silt loam
The soil is a heavy silt mix at 59.7%, with 21.3% clay and 18.9% sand. This gravelly silt loam texture offers excellent structural integrity for agriculture while maintaining enough clay to hold essential nutrients.
Reliable water capacity for crops
The county's available water capacity of 0.171 in/in matches the state average perfectly, ensuring consistent moisture for plants. Organic matter sits at 1.93%, which is slightly below the national average of 2.0% and the Tennessee average of 2.44%.
Well-drained soils for building
Classified as well-drained and belonging to hydrologic group B, these soils move water efficiently and present fewer risks for flooding. This combination makes Robertson County land ideal for both intensive farming and residential development.
Thriving in Hardiness Zone 7a
Zone 7a provides a long growing season for Robertson County gardeners to capitalize on these well-drained loams. It is an excellent environment for tobacco, corn, and cool-season vegetables like kale and carrots.
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: Gravelly silt loam
Typical soil profile. Actual depths vary by location.
USDA Soil Orders
Acidic Soil Detected
Your county's average pH is 5.6. These products help balance soil pH for healthier grass.
Browse Soil AmendmentsFrequently Asked Questions
What type of soil does Robertson County have?
Robertson County's soil is classified as Gravelly silt loam. This indicates the relative proportions of sand, silt, and clay — 19% sand, 60% 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 5.6, which is moderately acidic. This range suits many crops and is common across much of the eastern US.
What is the drainage class for Robertson County?
Robertson 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 Robertson County's soil?
Based on Robertson County's Gravelly silt loam texture, pH of 5.6, and Well drained, the soil is well suited for vegetables, grains, and most field crops, row crops and vegetable gardens, most annual and perennial crops.
What USDA soil order is found in Robertson County?
Robertson County's dominant soil order is Alfisols. Alfisols are moderate to high base-status soils with a clay-enriched subsoil. They support productive forests and cropland across temperate regions.
Soil & Planting Advisory: Robertson County
Soil Verdict
Robertson County is in USDA hardiness zone 7a, a moderate climate zone. where winter lows can reach 0°F. Mild winters mean soil rarely freezes deeply, allowing year-round microbial activity and faster organic matter breakdown.
Planting Guidance
Warm-season crops, citrus relatives, and heat-loving ornamentals do well. Cool-season vegetables should be planted in fall and winter. Winter protection (mulch, burlap wraps) helps push the zone boundary for desired species. 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
Warm soils accelerate organic matter breakdown, so compost and mulch need replenishing more frequently than in cooler zones. Sandy soils common in warm zones drain quickly; water-retentive amendments like compost or peat help hold moisture. When soil temperatures drop below freezing, microbial nitrogen cycling stops; spring fertilization is more effective than late-fall application.
Regional Context
Robertson County closely matches the Tennessee average hardiness conditions. The zone range of 7a-7b 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 Tennessee
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.