Polk County Soil Data
Polk County, Arkansas
USDA SSURGO / PHZMAvg pH
5.4
Texture
Loam
Drainage
N/A
Organic Matter
2.7%
Hydrologic Group
D
Data Story
About Soil in Polk County, Arkansas
Acidic soil in the Ouachita Mountains
Polk County features an average pH of 5.44, which is significantly more acidic than the national median of 6.5. While data for the taxonomic order is limited, the acidic profile suggests a landscape shaped by heavy weathering. This pH level falls slightly below the Arkansas state average of 5.56.
A gritty sand and silt mixture
The soil contains 43.5% sand and 38.6% silt, creating a texture that balances grit with fine particles. With only 15.3% clay, these soils are relatively easy to work but may struggle to hold onto nutrients. The high sand content promotes initial water entry but requires careful management to prevent leaching.
Healthy organic matter with low water storage
At 2.73%, the organic matter content exceeds the national average of 2.0% but remains below the state average of 4.15%. The available water capacity is 0.122 in/in, which is lower than the state benchmark of 0.148. This suggests that while the soil is biologically active, it may dry out quickly during Arkansas summers.
Challenging runoff and high water tables
The county belongs to hydrologic group D, indicating soil with a very slow infiltration rate and high runoff potential. This classification often points to a permanent high water table or a clay layer that restricts downward movement. Gardeners should consider raised beds to avoid saturated roots during the rainy season.
Diverse planting in hardiness zone 8a
Located in USDA hardiness zone 8a, Polk County is ideal for growing acid-loving plants like blueberries and azaleas. The soil score of 31.7 reflects the challenges of acidity and drainage, but proper amendments can lead to a productive harvest. Start your garden today by testing your specific plot to tailor your fertilization strategy.
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
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 Polk County have?
Polk County's soil is classified as Loam. This indicates the relative proportions of sand, silt, and clay — 43% sand, 39% silt, and 15% clay. Loamy soils hold moisture well and support a wide range of plants.
Is Polk County's soil acidic or alkaline?
Polk 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 Polk County?
Drainage class data is not currently available for Polk County.
What crops or plants grow well in Polk County's soil?
Based on Polk County's Loam texture, pH of 5.4, and drainage class, the soil is well suited for acid-loving plants like blueberries and azaleas, row crops and vegetable gardens.
What USDA soil order is found in Polk County?
The dominant USDA soil order for Polk County is not currently available in our dataset.
Soil & Planting Advisory: Polk County
Soil Verdict
Polk County is in USDA hardiness zone 8a, a warm climate zone. where winter lows can reach 10°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
Polk County closely matches the Arkansas average hardiness conditions. The zone range of 7b-8a within the county means soil and planting decisions should account for local elevation and topography.
Planning your lawn? View lawn care data for Polk County on LawnByCounty.com →
Other Counties in Arkansas
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.