Dubuque County Soil Data
Dubuque County, Iowa
USDA SSURGO / PHZMAvg pH
6.4
Texture
Loamy fine sand
Drainage
Excessively drained
Organic Matter
2.5%
Hydrologic Group
A
Data Story
About Soil in Dubuque County, Iowa
Entisols of the Driftless Area
Dubuque County is home to Entisols, which are young soils often found on steep or shifting landscapes. The average pH of 6.38 is very close to the Iowa state average of 6.43, providing a familiar chemical environment for local farmers. Its soil score of 71.4 sits just slightly below the state average of 72.9.
Loamy Fine Sand and High Silt
The dominant texture is loamy fine sand, though the overall county average is 52.5% silt and 27.5% sand. This mixture creates a unique physical profile that is easy to till but requires careful management to prevent erosion. The 19.3% clay content is relatively low, making the soil feel lighter and more porous.
Superior Water Capacity for Growing
Despite a lower organic matter content of 2.55%, Dubuque County features an impressive available water capacity of 0.197 in/in. This exceeds the state average of 0.195, meaning the soil is excellent at storing water for plant use. This trait is vital for maintaining productivity in the county's diverse topography.
Excessively Drained for Fast Drying
Classified as 'excessively drained' and part of Hydrologic Group A, this soil sheds water very quickly. While this prevents root rot, it also means plants may need more frequent watering during dry spells. These drainage characteristics are typical for the rugged, unglaciated terrain found in this part of the state.
Elevated Gardening in Zone 5a
In Zone 5a, Dubuque's fast-draining soils are ideal for plants that hate 'wet feet,' such as lavender or Mediterranean herbs. The high water capacity ensures that once you water, the soil holds that moisture deep where roots need it. Use the natural slopes of the county to create a stunning, well-drained terraced garden.
Soil Composition
Soil pH
Soil Series
Detailed soil series data not yet available for this county.
Hydrologic Group
Group A — Low Runoff
Sandy, well-drained soils with high infiltration rates. Water moves quickly through the soil profile. Lowest runoff potential when thoroughly wetted.
Drainage Class
Excessively drained
Water is removed very rapidly. Very sandy or gravelly soils with little water retention.
Soil Profile
Dominant texture: Loamy fine sand
Typical soil profile. Actual depths vary by location.
USDA Soil Orders
Sandy Soil Detected
Sandy soils drain quickly and can dry out. These products boost water retention and organic matter.
Browse Soil AmendmentsFrequently Asked Questions
What type of soil does Dubuque County have?
Dubuque County's soil is classified as Loamy fine sand. This indicates the relative proportions of sand, silt, and clay — 27% sand, 52% silt, and 19% clay. Loamy soils hold moisture well and support a wide range of plants.
Is Dubuque County's soil acidic or alkaline?
Dubuque 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 Dubuque County?
Dubuque County has a dominant drainage class of "Excessively drained." Moderate drainage allows adequate moisture retention while still permitting excess water to drain over time.
What crops or plants grow well in Dubuque County's soil?
Based on Dubuque County's Loamy fine sand texture, pH of 6.4, and Excessively drained, the soil is well suited for vegetables, grains, and most field crops, row crops and vegetable gardens.
What USDA soil order is found in Dubuque County?
Dubuque 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: Dubuque County
Soil Verdict
Dubuque 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
Dubuque County closely matches the Iowa average hardiness conditions.
Planning your lawn? View lawn care data for Dubuque 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.