Union County Soil Data
Union County, Indiana
USDA SSURGO / PHZMAvg pH
6.5
Texture
Silt loam
Drainage
Well drained
Organic Matter
2.3%
Hydrologic Group
C
Data Story
About Soil in Union County, Indiana
Union County’s Balanced Silt Loam Identity
Union County sits on Alfisols with a dominant silt loam texture. Its average pH of 6.45 aligns almost perfectly with the national median of 6.5 and exceeds the Indiana state average of 6.08.
Silt-Heavy Mix for Reliable Workability
The soil contains 59.2% silt and 19.1% clay, creating a smooth profile that is easy to till and manage. With 21.8% sand, the mix provides enough structural support to prevent the heavy compaction common in wetter regions.
Moderate Fertility and High Water Retention
Organic matter stands at 2.34%, which is higher than the national average but below the 4.90% state benchmark. However, the available water capacity of 0.214 in/in is superior to the state average of 0.202, protecting plants during dry spells.
Well-Drained Soils Support Active Agriculture
The county features well-drained soils belonging to hydrologic group C. This classification indicates moderate infiltration rates, making the land ideal for row crops without frequent ponding issues.
Hardy Crops Thrive in Zone 6a
Located in USDA hardiness zone 6a, Union County is a prime spot for corn, soybeans, and stone fruits. Home gardeners should take advantage of the high water capacity to cultivate thirsty vegetables like tomatoes and peppers.
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: 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 Union County have?
Union County's soil is classified as Silt loam. This indicates the relative proportions of sand, silt, and clay — 22% sand, 59% silt, and 19% clay. Loamy soils hold moisture well and support a wide range of plants.
Is Union County's soil acidic or alkaline?
Union 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 Union County?
Union 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 Union County's soil?
Based on Union County's Silt loam texture, pH of 6.5, 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 Union County?
Union County's dominant soil order is Alfisols. Alfisols are moderate to high base-status soils with a clay-enriched subsoil. They support productive forests and cropland across temperate regions.
Soil & Planting Advisory: Union County
Soil Verdict
Union 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
Union County closely matches the Indiana average hardiness conditions.
Planning your lawn? View lawn care data for Union County on LawnByCounty.com →
Other Counties in Indiana
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.