Washington County Soil Data
Washington County, Tennessee
USDA SSURGO / PHZMAvg pH
5.1
Texture
Silt loam
Drainage
Moderately well drained
Organic Matter
5.4%
Hydrologic Group
C
Data Story
About Soil in Washington County, Tennessee
Washington's Strongly Acidic Inceptisols
Washington County features a silt loam texture within the Inceptisol order, indicating relatively young soil development. At a pH of 5.06, these soils are significantly more acidic than the state average of 5.35. This sharp deviation from the national 6.5 median requires active intervention for traditional agriculture.
Silt-Driven Texture and Drainage
With 40.8% silt and 31.2% sand, these soils prioritize air space and drainage over heavy structure. The relatively low clay content of 18.0% helps prevent the soil from becoming overly compacted during wet seasons. This mix provides a smooth, workable surface for tilling and planting.
Exceptional Organic Richness
The county boasts a high organic matter content of 5.43%, more than doubling the Tennessee average of 2.44%. Despite an available water capacity of 0.155 in/in being below the state norm, the high organic content provides a massive natural nutrient boost. This profile makes it one of the most naturally enriched soils in the region.
Moderate Drainage for Silt Loams
Classified as moderately well drained, these soils belong to hydrologic group C, indicating somewhat slow infiltration rates. While the silt loam texture feels light, the subsurface can hold water after heavy storms. This requires careful consideration when planning septic systems or large-scale drainage projects.
Thriving in Washington's Zone 7b
The high organic matter in zone 7b is perfect for growing nutrient-hungry greens and root vegetables. Blueberries and other acid-loving shrubs will love the 5.06 pH right out of the box. Grab a spade and take advantage of this unusually rich organic foundation to start your home garden.
Soil Composition
Soil pH
Soil Series
Detailed soil series data not yet available for this county.
Hydrologic Group
Group C — Moderate-High Runoff
Soils with slow infiltration rates, often with a layer that impedes downward water movement. Higher clay content restricts drainage.
Drainage Class
Moderately well drained
Water is removed somewhat slowly. May have a slowly permeable layer or seasonal water table.
Soil Profile
Dominant texture: Silt loam
Typical soil profile. Actual depths vary by location.
USDA Soil Orders
Acidic Soil Detected
Your county's average pH is 5.1. These products help balance soil pH for healthier grass.
Browse Soil AmendmentsFrequently Asked Questions
What type of soil does Washington County have?
Washington County's soil is classified as Silt loam. This indicates the relative proportions of sand, silt, and clay — 31% sand, 41% silt, and 18% clay. Loamy soils hold moisture well and support a wide range of plants.
Is Washington County's soil acidic or alkaline?
Washington 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 Washington County?
Washington County has a dominant drainage class of "Moderately 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 Washington County's soil?
Based on Washington County's Silt loam texture, pH of 5.1, and Moderately well drained, the soil is well suited for acid-loving plants like blueberries and azaleas, row crops and vegetable gardens, most annual and perennial crops.
What USDA soil order is found in Washington County?
Washington County's dominant soil order is Inceptisols. Inceptisols are young soils with weak horizon development. They occur in a wide range of climates and parent materials.
Soil & Planting Advisory: Washington County
Soil Verdict
Washington County is in USDA hardiness zone 7b, a moderate climate zone. where winter lows can reach 5°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. 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.
Regional Context
Washington 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 Washington 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.