Ontonagon County Soil Data
Ontonagon County, Michigan
USDA SSURGO / PHZMAvg pH
4.1
Texture
Silt Loam
Drainage
N/A
Organic Matter
54.5%
Hydrologic Group
N/A
Data Story
About Soil in Ontonagon County, Michigan
Highly Acidic Upper Peninsula Soil
Ontonagon County features a very low average pH of 4.12, making it significantly more acidic than the national median of 6.5. This sharp acidity defines the local landscape and creates a specialized environment for native flora. Local growers must carefully manage this pH level to support common ornamental or edible plants.
Silty Texture with Low Sand
The soil is remarkably silty at 51.5%, paired with a low sand content of just 12.7%. This combination creates a smooth, flour-like texture that retains moisture much better than the sandier regions of the state. With only 6.6% clay, the soil remains relatively easy to work without becoming heavy or sticky.
Exceptional Organic Matter and Water Storage
This county leads in fertility metrics with a massive 54.49% organic matter content and an available water capacity of 0.397 in/in. These figures nearly double the state averages of 19.76% and 0.202 respectively, indicating a powerhouse of potential nutrient storage. The soil acts like a sponge, holding vast amounts of water and biological material for plant use.
Hydrology Defined by High Saturation
While specific drainage classes are not officially recorded here, the high available water capacity suggests slow-moving hydrology. The 51.5% silt content can lead to prolonged dampness, which is excellent for drought resistance but may require raised beds for plants that dislike 'wet feet.' Building projects will likely need to account for this significant water retention.
Cold-Hardy Growth in Zone 4b
Ontonagon sits in USDA Zone 4b, requiring plants that can withstand deep Michigan winters. The high organic content makes this an ideal spot for blueberries and other acid-loving shrubs that thrive in moist, rich environments. It is a fantastic place to start a woodland garden or a hardy vegetable patch with proper pH management.
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: Silt Loam
Typical soil profile. Actual depths vary by location.
USDA Soil Orders
Acidic Soil Detected
Your county's average pH is 4.1. These products help balance soil pH for healthier grass.
Browse Soil AmendmentsFrequently Asked Questions
What type of soil does Ontonagon County have?
Ontonagon County's soil is classified as Silt Loam. This indicates the relative proportions of sand, silt, and clay — 13% sand, 51% silt, and 7% clay. Loamy soils hold moisture well and support a wide range of plants.
Is Ontonagon County's soil acidic or alkaline?
Ontonagon County's soil has a low pH of 4.1, which is strongly acidic. Acidic soils benefit from lime applications to raise pH and improve nutrient availability.
What is the drainage class for Ontonagon County?
Drainage class data is not currently available for Ontonagon County.
What crops or plants grow well in Ontonagon County's soil?
Based on Ontonagon County's Silt Loam texture, pH of 4.1, and drainage class, the soil is well suited for acid-loving plants like blueberries and azaleas, row crops and vegetable gardens.
What USDA soil order is found in Ontonagon County?
The dominant USDA soil order for Ontonagon County is not currently available in our dataset.
Soil & Planting Advisory: Ontonagon County
Soil Verdict
Ontonagon County is in USDA hardiness zone 4b, a cold climate zone. where winter lows can reach -25°F. Soils here experience deep freeze cycles that can disrupt structure, kill shallow roots, and slow microbial activity for months each year.
Planting Guidance
Focus on cold-hardy perennials, native grasses, and conifers. The short growing window favors plants with low heat requirements. 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
Deep winter freezing can create soil heaving that pushes shallow-rooted plants out of the ground; add 3-4 inches of organic mulch each fall. Soil drainage is critical — frozen, waterlogged soil kills roots faster than cold alone. When soil temperatures drop below freezing, microbial nitrogen cycling stops; spring fertilization is more effective than late-fall application.
Regional Context
Ontonagon County is somewhat cooler than the Michigan statewide average. The zone range of 4b-5a within the county means soil and planting decisions should account for local elevation and topography.
Planning your lawn? View lawn care data for Ontonagon County on LawnByCounty.com →
Other Counties in Michigan
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.