Johnson County Soil Data
Johnson County, Iowa
Avg pH
6.3
Texture
Loam
Drainage
Moderately well drained
Organic Matter
3.3%
Hydrologic Group
D
Data Story
About Soil in Johnson County, Iowa
Johnson's Versatile Loam Soils
Johnson County is dominated by loamy soils from the Entisol order, providing a versatile foundation for growth. Its average pH of 6.25 is slightly more acidic than the national median of 6.5 and the Iowa average of 6.43.
The Ideal Texture Mix
The soil features a balanced mix of 54.1% silt, 24.7% sand, and 20.6% clay. This loamy texture is widely considered the gold standard for workability and drainage in both gardening and large-scale farming.
High Organic Matter Content
Johnson County boasts 3.32% organic matter, which is considerably higher than the national average of 2.0%. While the water capacity of 0.184 in/in is slightly below the state average, the high organic content keeps the soil fertile.
Moderately Well-Drained Grounds
The county's soils are mostly moderately well drained, making them adaptable for different uses. Classified in hydrologic group D, the soil may have a higher runoff potential during heavy storms, requiring mindful landscape planning.
Thriving Gardens in Zone 5b
Zone 5b provides a reliable window for growing everything from sweet corn to decorative perennials. Grab some seeds and start a garden, as these loamy soils are easy to dig and exceptionally rewarding.
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
Moderately well drained
Water is removed somewhat slowly. May have a slowly permeable layer or seasonal water table.
Soil Profile
Dominant texture: Loam
Typical soil profile. Actual depths vary by location.
USDA Soil Orders
Frequently Asked Questions
What type of soil does Johnson County have?
Johnson County's soil is classified as Loam. This indicates the relative proportions of sand, silt, and clay — 25% sand, 54% silt, and 21% clay. Loamy soils hold moisture well and support a wide range of plants.
Is Johnson County's soil acidic or alkaline?
Johnson County's soil has a pH of 6.3, which is moderately acidic. This range suits many crops and is common across much of the eastern US.
What is the drainage class for Johnson County?
Johnson 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 Johnson County's soil?
Based on Johnson County's Loam texture, pH of 6.3, and Moderately well drained, the soil is well suited for vegetables, grains, and most field crops, row crops and vegetable gardens, most annual and perennial crops.
What USDA soil order is found in Johnson County?
Johnson County's dominant soil order is Entisols. Entisols are recently formed soils with little to no horizon development. They are common on floodplains, steep slopes, and sandy deposits.
Planning your lawn? View lawn care data for Johnson 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.