Polk County Soil Data
Polk County, Iowa
Avg pH
6.4
Texture
Loam
Drainage
N/A
Organic Matter
4.3%
Hydrologic Group
N/A
Data Story
About Soil in Polk County, Iowa
The State Standard for Soil
Polk County’s pH of 6.41 is almost identical to the Iowa state average of 6.43. This creates a perfectly balanced environment that supports a wide variety of Midwestern vegetation.
Silty Texture with Sandy Pockets
The soil contains 45.4% silt and nearly 30% sand, providing better drainage than many neighboring counties. This 29.6% sand content makes the ground easier to work for home gardeners.
High Organic Matter and Productivity
At 4.26%, the organic matter level is well above the state average of 3.81%. This high carbon content contributes to a solid soil score of 77.0, indicating prime agricultural land.
Moderate Hydrology in the Heartland
With an available water capacity of 0.192 in/in, the soil remains consistently moist. Though formal drainage classes are not listed, the sand-silt ratio suggests moderate water movement through the profile.
Abundant Growth in Zone 5b
Polk County sits in Zone 5b, perfect for everything from sunflowers to bell peppers. Start your urban or rural garden now to take advantage of this top-tier Iowa soil.
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: Loam
Typical soil profile. Actual depths vary by location.
USDA Soil Orders
Frequently 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 — 30% sand, 45% silt, and 23% 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 pH of 6.4, which is moderately acidic. This range suits many crops and is common across much of the eastern US.
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 6.4, 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 Polk County?
The dominant USDA soil order for Polk County is not currently available in our dataset.
Planning your lawn? View lawn care data for Polk County on LawnByCounty.com →
Other Counties in Iowa
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.