Madison County Soil Data
Madison County, Illinois
USDA SSURGO / PHZMAvg pH
6.4
Texture
Silt Loam
Drainage
N/A
Organic Matter
2.2%
Hydrologic Group
N/A
Data Story
About Soil in Madison County, Illinois
Balanced pH for Southern Illinois Growth
Madison County soil features an average pH of 6.45, nearly identical to the national median of 6.5. While specific taxonomic classifications are currently unrecorded, this near-neutral acidity supports a wide range of nutrient availability for local crops.
A Silt-Heavy Foundation
The soil profile is dominated by 64.8% silt and 23.1% clay, which provides excellent structure for holding nutrients. With only 12.1% sand, this mix is highly workable but can be prone to surface crusting after heavy rains.
Solid Water Capacity and Organic Richness
Organic matter stands at 2.24%, which beats the national average of 2.0% even if it trails the Illinois state average of 2.94%. The available water capacity of 0.206 in/in is slightly higher than the state average, ensuring reliable moisture during the summer heat.
Observing Local Runoff and Absorption
While specific drainage classes and hydrologic groups are not currently documented in federal databases, the high silt content suggests moderate natural drainage. Gardeners should monitor for standing water to decide if raised beds are necessary for their specific site.
Thriving in Hardiness Zone 7a
The county sits in Zone 7a, offering a longer growing season than most of Illinois. This climate and a 74.5 soil score make it a prime spot for planting anything from late-season tomatoes to hardy fruit trees.
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
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Browse Soil AmendmentsFrequently Asked Questions
What type of soil does Madison County have?
Madison County's soil is classified as Silt Loam. This indicates the relative proportions of sand, silt, and clay — 12% sand, 65% silt, and 23% clay. Loamy soils hold moisture well and support a wide range of plants.
Is Madison County's soil acidic or alkaline?
Madison County's soil has a pH of 6.4, which is moderately acidic. This range suits many crops and is common across much of the eastern US.
What is the drainage class for Madison County?
Drainage class data is not currently available for Madison County.
What crops or plants grow well in Madison County's soil?
Based on Madison County's Silt Loam texture, pH of 6.4, 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 Madison County?
The dominant USDA soil order for Madison County is not currently available in our dataset.
Soil & Planting Advisory: Madison County
Soil Verdict
Madison County is in USDA hardiness zone 7a, a moderate climate zone. where winter lows can reach 0°F. Mild winters mean soil rarely freezes deeply, allowing year-round microbial activity and faster organic matter breakdown.
Planting Guidance
Warm-season crops, citrus relatives, and heat-loving ornamentals do well. Cool-season vegetables should be planted in fall and winter. 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
Warm soils accelerate organic matter breakdown, so compost and mulch need replenishing more frequently than in cooler zones. Sandy soils common in warm zones drain quickly; water-retentive amendments like compost or peat help hold moisture. When soil temperatures drop below freezing, microbial nitrogen cycling stops; spring fertilization is more effective than late-fall application.
Regional Context
Madison County is somewhat warmer than the Illinois statewide average. The zone range of 6b-7a within the county means soil and planting decisions should account for local elevation and topography.
Planning your lawn? View lawn care data for Madison 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.