Sullivan County Soil Data
Sullivan County, Missouri
USDA SSURGO / PHZMAvg pH
6.3
Texture
Silty clay loam
Drainage
Well drained
Organic Matter
2.8%
Hydrologic Group
C
Data Story
About Soil in Sullivan County, Missouri
Balanced Entisols in North Missouri
Sullivan County's Entisols have a pH of 6.34, placing it much closer to the national median of 6.5 than many other Missouri counties. This silty clay loam provides a solid chemical foundation for diverse plant life.
The Strength of Silty Clay Loam
With 48.7% silt and 26.2% clay, this soil holds onto nutrients effectively while maintaining structure. The 25.1% sand helps prevent the heavy clay from becoming completely unworkable during wet seasons.
Superior Water Retention for Crops
The available water capacity of 0.197 in/in exceeds the state average of 0.183, signaling excellent drought resistance. However, the organic matter at 2.82% is lower than the Missouri state average of 4.74%.
Well Drained for Stable Growth
This well-drained soil falls into hydrologic group C, meaning it has a slow infiltration rate when thoroughly wet. It offers a stable environment for construction while supporting robust agricultural runoff management.
Hardy Plants for Zone 6a
Falling in hardiness zone 6a, this county is perfect for hardy perennials and cold-weather greens. Get your garden started early to take advantage of the superior water-holding capacity of your soil.
Soil Composition
Soil pH
Soil Series
Detailed soil series data not yet available for this county.
Hydrologic Group
Group C — Moderate-High Runoff
Soils with slow infiltration rates, often with a layer that impedes downward water movement. Higher clay content restricts drainage.
Drainage Class
Well drained
Water is removed from the soil readily but not rapidly. Optimal for most plants and construction.
Soil Profile
Dominant texture: Silty clay loam
Typical soil profile. Actual depths vary by location.
USDA Soil Orders
Clay Soil Detected
Clay soils can struggle with drainage. These products improve soil structure and water flow.
Browse Soil AmendmentsFrequently Asked Questions
What type of soil does Sullivan County have?
Sullivan County's soil is classified as Silty clay loam. This indicates the relative proportions of sand, silt, and clay — 25% sand, 49% silt, and 26% clay. Loamy soils hold moisture well and support a wide range of plants.
Is Sullivan County's soil acidic or alkaline?
Sullivan 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 Sullivan County?
Sullivan County has a dominant drainage class of "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 Sullivan County's soil?
Based on Sullivan County's Silty clay loam texture, pH of 6.3, and 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 Sullivan County?
Sullivan 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.
Soil & Planting Advisory: Sullivan County
Soil Verdict
Sullivan County is in USDA hardiness zone 6a, a moderate climate zone. where winter lows can reach -10°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
Sullivan County closely matches the Missouri average hardiness conditions. The zone range of 5b-6a within the county means soil and planting decisions should account for local elevation and topography.
Planning your lawn? View lawn care data for Sullivan County on LawnByCounty.com →
Other Counties in Missouri
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.