Knox County Soil Data
Knox County, Illinois
USDA SSURGO / PHZMAvg pH
6.5
Texture
Silt Loam
Drainage
N/A
Organic Matter
2.2%
Hydrologic Group
N/A
Data Story
About Soil in Knox County, Illinois
Solid Agricultural Foundations in Knox
Knox County's soil features an average pH of 6.46, which is nearly identical to the national median of 6.5. This balanced acidity facilitates easy nutrient uptake for both row crops and garden perennials.
Classic Silt-Clay Balance
The soil contains 67.0% silt and 22.8% clay, with just 10.2% sand. This mix creates a classic Illinois profile that is heavy enough to hold nutrients but silty enough to remain workable for farmers.
Efficient Water Use and Stable Matter
Organic matter is 2.23%, which is healthy by national standards but slightly lower than the Illinois average of 2.94%. Its available water capacity of 0.211 in/in is superior to the state average, providing good drought resistance.
High-Quality Midwestern Land
With a soil score of 76.2, Knox County outperforms the state average of 73.6 for land productivity. Although specific drainage class data is limited, these scores suggest the soil is generally reliable for both agriculture and construction.
Reliable Results in Zone 5b
In hardiness zone 5b, Knox County is well-suited for traditional Midwestern staples like beans, corn, and tomatoes. The high water capacity ensures that your garden will remain resilient even during the hottest weeks of July.
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 Knox County have?
Knox County's soil is classified as Silt Loam. This indicates the relative proportions of sand, silt, and clay — 10% sand, 67% silt, and 23% clay. Loamy soils hold moisture well and support a wide range of plants.
Is Knox County's soil acidic or alkaline?
Knox 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 Knox County?
Drainage class data is not currently available for Knox County.
What crops or plants grow well in Knox County's soil?
Based on Knox 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 Knox County?
The dominant USDA soil order for Knox County is not currently available in our dataset.
Soil & Planting Advisory: Knox County
Soil Verdict
Knox County is in USDA hardiness zone 5b, a cold climate zone. where winter lows can reach -15°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
Knox County is somewhat cooler than the Illinois statewide average.
Planning your lawn? View lawn care data for Knox 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.