Iron County Soil Data
Iron County, Missouri
USDA SSURGO / PHZMAvg pH
5.6
Texture
Silty clay loam
Drainage
Well drained
Organic Matter
14.7%
Hydrologic Group
C
Data Story
About Soil in Iron County, Missouri
Acidic Silty Clay Loam Entisols
Iron County is characterized by silty clay loam soils within the Entisols order, showing an average pH of 5.64. This is significantly more acidic than the national 6.5 median and the state's 6.09 average. These young, undeveloped soils are typical of the rugged, rocky terrain found in the St. Francois Mountains.
Lower Clay Mix with High Silt
The soil contains 48.5% silt and only 11.6% clay, making it one of the less clayey profiles in the state. Sand accounts for 21.8% of the mix, contributing to a texture that is easier to work than heavy clays. However, the low clay content can limit the soil's ability to hold onto certain nutrients over time.
Extreme Organic Matter Levels Recorded
Iron County boasts a massive 14.70% organic matter content, nearly triple the Missouri state average of 4.74%. Despite this richness, the Available Water Capacity is very low at 0.152 in/in, well below the state benchmark of 0.183 in/in. This suggests that while the soil is nutrient-dense, it is very porous and drains water quickly.
Well Drained with High Runoff Risk
Classified as well drained, the soil belongs to hydrologic group C, which means it has a slow infiltration rate. This can lead to significant surface runoff during heavy Ozark rains despite the soil's ability to eventually dry out. Builders should be cautious of erosion and water management when working on slopes.
Mountain Gardening in Zone 6b
The 6b Hardiness Zone and incredible organic matter levels make this area unique for specialized gardening. A soil score of 58.3 suggests challenges, but native plants and acid-loving berries will thrive here. Embrace the natural richness of the soil and plant a forest garden that loves the mountain air.
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
Acidic Soil Detected
Your county's average pH is 5.6. These products help balance soil pH for healthier grass.
Browse Soil AmendmentsFrequently Asked Questions
What type of soil does Iron County have?
Iron County's soil is classified as Silty clay loam. This indicates the relative proportions of sand, silt, and clay — 22% sand, 49% silt, and 12% clay. Loamy soils hold moisture well and support a wide range of plants.
Is Iron County's soil acidic or alkaline?
Iron County's soil has a pH of 5.6, which is moderately acidic. This range suits many crops and is common across much of the eastern US.
What is the drainage class for Iron County?
Iron 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 Iron County's soil?
Based on Iron County's Silty clay loam texture, pH of 5.6, 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 Iron County?
Iron 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: Iron County
Soil Verdict
Iron 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
Iron County closely matches the Missouri average hardiness conditions.
Planning your lawn? View lawn care data for Iron 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.