Custer County Soil Data
Custer County, Montana
USDA SSURGO / PHZMAvg pH
7.6
Texture
Loam
Drainage
N/A
Organic Matter
1.8%
Hydrologic Group
N/A
Data Story
About Soil in Custer County, Montana
Alkaline Soils in the Big Sky Country
Custer County features alkaline soils with an average pH of 7.57, which sits higher than the national median of 6.5 and the state average of 7.43. While taxonomic data is limited, these levels indicate a chemical environment that favors specific minerals over others. Growers should prepare for soil that is naturally less acidic than the typical American yard.
A Balanced Mix of Silt and Sand
The soil contains 34.7% sand, 41.4% silt, and 23.8% clay. This composition provides a balanced texture that generally offers better workability than heavy clay regions. The high silt content helps with structural stability while the sand assists with initial water infiltration.
Moderate Fertility and Standard Water Retention
Organic matter levels reach 1.79%, falling below the state average of 2.54% and the national average of 2.0%. Despite lower organic content, the available water capacity of 0.165 in/in perfectly matches the Montana state average. This suggests a soil that holds onto moisture effectively even with less natural decomposition.
Steady Moisture and Limited Drainage Data
While specific drainage classes are not currently recorded, the silty texture indicates moderate permeability. Landowners should monitor for surface runoff during the spring thaw. The overall soil score of 36.2 suggests there are some challenges to productivity compared to the state average of 43.1.
Cultivating Crops in Zone 4b
With a USDA Hardiness Zone of 4b, Custer County is ideal for hearty grains and cold-tolerant garden staples. Focus on alkaline-loving plants like lilacs, clematis, and asparagus. Your garden can thrive here if you focus on building up that organic matter over time.
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
Alkaline Soil Detected
Your county's average pH is 7.6. These products help acidify soil for better nutrient uptake.
Browse Soil AmendmentsFrequently Asked Questions
What type of soil does Custer County have?
Custer County's soil is classified as Loam. This indicates the relative proportions of sand, silt, and clay — 35% sand, 41% silt, and 24% clay. Loamy soils hold moisture well and support a wide range of plants.
Is Custer County's soil acidic or alkaline?
Custer County's soil has a pH of 7.6, which is mildly to moderately alkaline. Sulfur amendments can lower pH if needed.
What is the drainage class for Custer County?
Drainage class data is not currently available for Custer County.
What crops or plants grow well in Custer County's soil?
Based on Custer County's Loam texture, pH of 7.6, and drainage class, the soil is well suited for drought-tolerant crops and native grasses, row crops and vegetable gardens.
What USDA soil order is found in Custer County?
The dominant USDA soil order for Custer County is not currently available in our dataset.
Soil & Planting Advisory: Custer County
Soil Verdict
Custer 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
Custer County closely matches the Montana average hardiness conditions. The zone range of 4a-4b within the county means soil and planting decisions should account for local elevation and topography.
Planning your lawn? View lawn care data for Custer County on LawnByCounty.com →
Other Counties in Montana
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.