Washington County Soil Data
Washington County, Oklahoma
USDA SSURGO / PHZMAvg pH
5.4
Texture
Water
Drainage
N/A
Organic Matter
1.9%
Hydrologic Group
N/A
Data Story
About Soil in Washington County, Oklahoma
Strongly Acidic Ground in Northeast Oklahoma
Washington County averages a pH of 5.38, placing it well below the state average of 6.06 and the national median of 6.5. This significant acidity can limit the availability of certain nutrients unless the soil is specifically managed.
A Silty Mix with Moderate Structure
The soil composition is 39.9% silt and 27.1% sand, which creates a silty texture that resists crusting. A clay fraction of 19.9% provides enough structure to hold fertilizers effectively without the heaviness of pure clay.
Rich Organic Matter and High Water Storage
At 1.91%, the organic matter content is higher than the Oklahoma average of 1.72%. This is paired with an available water capacity of 0.155 in/in, which is among the better water-retention scores in the state.
Monitoring Runoff in Silty Conditions
While specific drainage classes are not recorded for the dominant soil types here, the high silt content influences surface runoff patterns. Homeowners should observe how heavy rains move across their property before starting major landscaping projects.
Vibrant Gardens in Hardiness Zone 7a
The combination of high organic matter and good water storage makes Zone 7a ideal for tomatoes and leafy greens. Your soil has the biological foundation to support a very lush and healthy landscape.
Soil Composition
Soil pH
Soil Series
Detailed soil series data not yet available for this county.
Hydrologic Group
Hydrologic group data not available.
Drainage Class
Drainage class data not available.
Soil Profile
Dominant texture: Water
Typical soil profile. Actual depths vary by location.
USDA Soil Orders
Acidic Soil Detected
Your county's average pH is 5.4. 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 Water. This indicates the relative proportions of sand, silt, and clay — 27% sand, 40% silt, and 20% clay. Sandy soils drain quickly but may need more frequent irrigation and fertilization.
Is Washington County's soil acidic or alkaline?
Washington County's soil has a low pH of 5.4, 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?
Drainage class data is not currently available for Washington County.
What crops or plants grow well in Washington County's soil?
Based on Washington County's Water texture, pH of 5.4, and drainage class, the soil is well suited for acid-loving plants like blueberries and azaleas.
What USDA soil order is found in Washington County?
The dominant USDA soil order for Washington County is not currently available in our dataset.
Soil & Planting Advisory: Washington County
Soil Verdict
Washington 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
Washington County closely matches the Oklahoma average hardiness conditions.
Planning your lawn? View lawn care data for Washington County on LawnByCounty.com →
Other Counties in Oklahoma
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.