Black Hawk County Soil Data
Black Hawk County, Iowa
USDA SSURGO / PHZMAvg pH
6.3
Texture
Loam
Drainage
N/A
Organic Matter
4.1%
Hydrologic Group
N/A
Data Story
About Soil in Black Hawk County, Iowa
Slightly Acidic Soils of Black Hawk
Black Hawk County features a pH of 6.32, which is slightly more acidic than the state average of 6.43. Despite a lower soil score of 66.6, the area is renowned for its agricultural history.
Sand-Heavy Mix Warms Quickly
The soil has a high sand content of 39.9% and 39.5% silt, creating a lighter texture than many other Iowa counties. This composition helps the ground warm up quickly in the spring, though it may dry out faster.
Rich Organic Matter Beats State Average
At 4.08%, organic matter here is significantly higher than the state average of 3.81%. However, the available water capacity is lower at 0.170 in/in, so supplemental irrigation may be necessary during August heat.
Porous Soils with Rapid Movement
Formal drainage classes are not provided for this county, but the 40% sand content points toward rapid water movement. Gardeners should watch for nutrient leaching due to this porous structure.
Success with Root Crops in Zone 5a
Zone 5a gardeners will find success with root vegetables like potatoes that appreciate the looser, sandy soil. This is a perfect spot for a raised bed garden to capitalize on that high organic matter.
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: 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 Black Hawk County have?
Black Hawk County's soil is classified as Loam. This indicates the relative proportions of sand, silt, and clay — 40% sand, 39% silt, and 20% clay. Loamy soils hold moisture well and support a wide range of plants.
Is Black Hawk County's soil acidic or alkaline?
Black Hawk 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 Black Hawk County?
Drainage class data is not currently available for Black Hawk County.
What crops or plants grow well in Black Hawk County's soil?
Based on Black Hawk County's Loam texture, pH of 6.3, 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 Black Hawk County?
The dominant USDA soil order for Black Hawk County is not currently available in our dataset.
Soil & Planting Advisory: Black Hawk County
Soil Verdict
Black Hawk County is in USDA hardiness zone 5a, a cold climate zone. where winter lows can reach -20°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. With extreme winter lows, any marginally hardy plants need heavy mulch and wind protection. 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
Black Hawk County closely matches the Iowa average hardiness conditions.
Planning your lawn? View lawn care data for Black Hawk County on LawnByCounty.com →
Other Counties in Iowa
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.