Spokane County Soil Data
Spokane County, Washington
Avg pH
5.6
Texture
Loam
Drainage
N/A
Organic Matter
33.3%
Hydrologic Group
N/A
Data Story
About Soil in Spokane County, Washington
Spokane's Acidic Ground
Spokane County has an average soil pH of 5.59, leaning significantly more acidic than the state average of 6.20. This value sits nearly a full point below the national median of 6.5. Gardeners may need to add lime to support pH-sensitive crops.
A Silty, Smooth Texture
The soil composition features 30.6% silt and 18.4% sand, with a very low clay content of only 7.8%. This high silt percentage gives the soil a smooth texture that is easy to work but can be prone to erosion if left uncovered. It provides a fine-grained medium for root growth.
Above Average Organic Content
The soil is rich with 33.28% organic matter, more than doubling the Washington state average of 14.85%. Despite this richness, the available water capacity of 0.181 in/in is slightly below the state average of 0.194. This means the soil is fertile but requires consistent irrigation.
Water Storage and Flow
While specific drainage classes aren't listed, the low clay content suggests the soil avoids heavy compaction and waterlogging. The available water capacity is respectable but slightly lower than the state norm, highlighting the need for good water management. Proper mulching can help retain that precious moisture.
Nurturing Zone 6b Gardens
Spokane County's Hardiness Zone 6b supports a variety of hardy vegetables and perennials. The exceptionally high organic matter provides a wonderful foundation for high-yield food gardens and beautiful landscapes. Start your growing journey in this rich, inland soil today.
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
Frequently Asked Questions
What type of soil does Spokane County have?
Spokane County's soil is classified as Loam. This indicates the relative proportions of sand, silt, and clay — 18% sand, 31% silt, and 8% clay. Loamy soils hold moisture well and support a wide range of plants.
Is Spokane County's soil acidic or alkaline?
Spokane County's soil has a pH of 5.6, which is moderately acidic. This range suits many crops and is common across much of the eastern US.
What is the drainage class for Spokane County?
Drainage class data is not currently available for Spokane County.
What crops or plants grow well in Spokane County's soil?
Based on Spokane County's Loam texture, pH of 5.6, 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 Spokane County?
The dominant USDA soil order for Spokane County is not currently available in our dataset.
Planning your lawn? View lawn care data for Spokane County on LawnByCounty.com →
Other Counties in Washington
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.