Cook County Soil Data
Cook County, Illinois
Avg pH
6.5
Texture
Silt Loam
Drainage
N/A
Organic Matter
5.7%
Hydrologic Group
N/A
Data Story
About Soil in Cook County, Illinois
Neutral Soils in the Urban Heart
Cook County features a stable soil pH of 6.52, aligning almost perfectly with the national median of 6.5. This neutral profile is slightly higher than the Illinois state average of 6.39, making it exceptionally friendly for urban gardening. Despite the heavy development, the underlying soil chemistry remains highly favorable for plant life.
A Varied Silt and Clay Mix
The soil composition here is 52.6% silt and 24.2% clay, with a nearly 20% sand component. This mixture offers a bit more physical variety than the silt-dominated counties downstate, which can help with water movement in an urban environment. The clay content provides the necessary structure to hold onto nutrients in busy landscapes.
Exceptional Organic Matter Levels
Cook County boasts a remarkable 5.66% organic matter, nearly doubling the state average of 2.94%. This unusually high level likely reflects the legacy of rich lakefront deposits and centuries of organic accumulation. However, available water capacity is slightly lower at 0.188 in/in, meaning these organic-rich soils may dry out faster than typical Illinois prairie ground.
Urban Water Management Challenges
While drainage class data is missing, the 24.2% clay content suggests that water can linger in compacted urban areas. The water capacity of 0.188 in/in is slightly below the state average, which might increase runoff during heavy Chicago rainstorms. For local gardeners, ensuring good drainage is key to making the most of the high organic matter.
Urban Oasis in Zone 6a
In Zone 6a, Cook County is perfect for a wide range of plants, from city-tolerant shrubs to vibrant rooftop vegetable gardens. With a massive 5.66% organic matter, your soil is naturally supercharged for growth. Whether you have a small backyard or a few containers, this fertile ground is ready for a spectacular growing season.
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: Silt Loam
Typical soil profile. Actual depths vary by location.
USDA Soil Orders
Frequently Asked Questions
What type of soil does Cook County have?
Cook County's soil is classified as Silt Loam. This indicates the relative proportions of sand, silt, and clay — 20% sand, 53% silt, and 24% clay. Loamy soils hold moisture well and support a wide range of plants.
Is Cook County's soil acidic or alkaline?
Cook County's soil has a pH of 6.5, which is near neutral. This range is ideal for most garden plants and field crops.
What is the drainage class for Cook County?
Drainage class data is not currently available for Cook County.
What crops or plants grow well in Cook County's soil?
Based on Cook County's Silt Loam texture, pH of 6.5, 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 Cook County?
The dominant USDA soil order for Cook County is not currently available in our dataset.
Planning your lawn? View lawn care data for Cook County on LawnByCounty.com →
Other Counties in Illinois
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.