Polk County Soil Data
Polk County, Wisconsin
USDA SSURGO / PHZMAvg pH
5.2
Texture
Loam
Drainage
Well drained
Organic Matter
10.7%
Hydrologic Group
B
Data Story
About Soil in Polk County, Wisconsin
Loamy Mollisols define the Polk landscape
Polk County features a loam texture classified under the Mollisols taxonomic order. With an average pH of 5.17, these soils are significantly more acidic than the national median of 6.5 and fall below the Wisconsin average of 5.63.
A sandy loam mix for easy working
The soil composition is 51.0% sand, 29.0% silt, and 8.4% clay. This high sand content ensures the ground is easy to work and provides decent aeration for root systems.
High organic matter fuels plant growth
Polk boasts an impressive 10.72% organic matter content, which is five times higher than the national average. While its available water capacity of 0.187 in/in is slightly below the state average of 0.204, the rich organic levels support strong growing potential.
Well-drained soils favor active farming
The county's soils are primarily well-drained and fall into hydrologic group B. This combination means water moves through the profile effectively, reducing the risk of ponding during heavy Wisconsin rains.
Hardy gardens thrive in Zone 4b
Located in USDA Hardiness Zone 4b, Polk County is ideal for cold-hardy vegetables and fruit trees. Gardeners should consider adding lime to balance the 5.17 pH for optimal nutrient uptake in their backyard plots.
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: Loam
Typical soil profile. Actual depths vary by location.
USDA Soil Orders
Acidic Soil Detected
Your county's average pH is 5.2. 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 — 51% sand, 29% silt, and 8% 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 5.2, 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?
Polk 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 Polk County's soil?
Based on Polk County's Loam texture, pH of 5.2, and 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 Polk County?
Polk County's dominant soil order is Mollisols. Mollisols are fertile, dark-colored soils that formed under grassland vegetation. They are among the most productive agricultural soils in the world.
Soil & Planting Advisory: Polk County
Soil Verdict
Polk County is in USDA hardiness zone 4b, a cold climate zone. where winter lows can reach -25°F. Soils here experience deep freeze cycles that can disrupt structure, kill shallow roots, and slow microbial activity for months each year.
Planting Guidance
Focus on cold-hardy perennials, native grasses, and conifers. The short growing window favors plants with low heat requirements. With extreme winter lows, any marginally hardy plants need heavy mulch and wind protection. 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
Deep winter freezing can create soil heaving that pushes shallow-rooted plants out of the ground; add 3-4 inches of organic mulch each fall. Soil drainage is critical — frozen, waterlogged soil kills roots faster than cold alone. When soil temperatures drop below freezing, microbial nitrogen cycling stops; spring fertilization is more effective than late-fall application.
Regional Context
Polk County is somewhat cooler than the Wisconsin statewide average. The zone range of 4a-4b 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 Wisconsin
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.