Clark County Soil Data
Clark County, Illinois
USDA SSURGO / PHZMAvg pH
6.5
Texture
Silt Loam
Drainage
N/A
Organic Matter
2.1%
Hydrologic Group
N/A
Data Story
About Soil in Clark County, Illinois
Steady Neutrality in Clark County
Clark County soil maintains an average pH of 6.47, placing it very close to the national median of 6.5 and slightly above the Illinois average. While specific taxonomic orders are currently unclassified in our data, this pH level is favorable for a wide variety of Midwestern crops. It provides a stable environment for most suburban and rural land uses.
Balanced Mix for Easy Management
The composition is 60.4% silt and 19.0% clay, supported by 20.6% sand. This relatively higher sand content compared to central Illinois neighbors makes the soil slightly easier to work and faster to warm up in the spring. It strikes a good balance between retaining nutrients and allowing for manageable drainage.
Leaner Organic Matter in the East
Organic matter in Clark County averages 2.07%, which meets the national average but trails the state average of 2.94%. The available water capacity is 0.189 in/in, meaning the soil holds slightly less moisture than the Illinois standard of 0.204 in/in. Gardeners here may find that adding compost helps boost these levels to match the state's top-performing counties.
Managing Moderate Moisture Levels
Without a formal drainage classification, we look to the 19.0% clay and 0.189 in/in water capacity for clues. These numbers suggest a soil that drains more freely than the heavy clay belts to the south, reducing the risk of standing water. This makes it a reliable choice for building foundations and diverse landscaping projects.
Warming Up in Zone 6b
As part of Zone 6b, Clark County enjoys a slightly longer growing season than its northern neighbors. This soil and climate combo is perfect for fruit trees like peaches and apples, as well as standard garden staples. If you start with a little organic fertilizer, your backyard garden will thrive in these well-balanced soils.
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
Soil Amendment Products
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Browse Soil AmendmentsFrequently Asked Questions
What type of soil does Clark County have?
Clark County's soil is classified as Silt Loam. This indicates the relative proportions of sand, silt, and clay — 21% sand, 60% silt, and 19% clay. Loamy soils hold moisture well and support a wide range of plants.
Is Clark County's soil acidic or alkaline?
Clark County's soil has a pH of 6.5, which is moderately acidic. This range suits many crops and is common across much of the eastern US.
What is the drainage class for Clark County?
Drainage class data is not currently available for Clark County.
What crops or plants grow well in Clark County's soil?
Based on Clark 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 Clark County?
The dominant USDA soil order for Clark County is not currently available in our dataset.
Soil & Planting Advisory: Clark County
Soil Verdict
Clark County is in USDA hardiness zone 6b, a moderate climate zone. where winter lows can reach -5°F. Freeze-thaw cycles are moderate; soil biology slows in winter but recovers reliably in spring, supporting a broad range of plants.
Planting Guidance
A wide plant palette is possible: deciduous trees, most shrubs, cool-season vegetables, and many perennials thrive here. Winter protection (mulch, burlap wraps) helps push the zone boundary for desired species. 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
Moderate freeze-thaw cycles naturally aerate the soil but can also cause compaction in clay-heavy areas; annual core aeration is beneficial. Organic matter amendments decompose at a moderate pace — aim for 3-5% organic content for optimal fertility. When soil temperatures drop below freezing, microbial nitrogen cycling stops; spring fertilization is more effective than late-fall application.
Regional Context
Clark County closely matches the Illinois average hardiness conditions. The zone range of 6a-6b within the county means soil and planting decisions should account for local elevation and topography.
Planning your lawn? View lawn care data for Clark 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.