Island County Soil Data
Island County, Washington
USDA SSURGO / PHZMAvg pH
5.3
Texture
Sandy Loam
Drainage
N/A
Organic Matter
44.4%
Hydrologic Group
N/A
Data Story
About Soil in Island County, Washington
Acidic and Rich Maritime Soil
Island County features an acidic pH of 5.35, which is well below the national median of 6.5 and the state average of 6.20. This chemical profile is common in coastal areas where high precipitation naturally leaches minerals from the soil.
Sandy Loam with High Porosity
The soil is comprised of 52.6% sand and 34.8% silt, with a low 9.2% clay content. This composition creates a light, workable texture that allows roots to penetrate deeply and prevents the ground from becoming waterlogged.
Extraordinary Organic Matter
The soil boasts a massive 44.39% organic matter, nearly triple the state average of 14.85%. With an available water capacity of 0.304 in/in, this soil acts like a sponge, providing incredible nutrient storage for plants.
Absorbent and Resilient Ground
Specific drainage classes are not listed, but the high organic content and sand percentage suggest excellent water absorption. This capacity is vital for managing the frequent rains and protecting the local water table.
Abundant Harvests in Zone 8b
Hardiness Zone 8b is ideal for cool-season crops like peas, berries, and leafy greens. With such rich organic soil and a mild climate, you have everything you need to start a flourishing home garden.
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: Sandy Loam
Typical soil profile. Actual depths vary by location.
USDA Soil Orders
Acidic Soil Detected
Your county's average pH is 5.3. These products help balance soil pH for healthier grass.
Browse Soil AmendmentsFrequently Asked Questions
What type of soil does Island County have?
Island County's soil is classified as Sandy Loam. This indicates the relative proportions of sand, silt, and clay — 53% sand, 35% silt, and 9% clay. Loamy soils hold moisture well and support a wide range of plants.
Is Island County's soil acidic or alkaline?
Island County's soil has a low pH of 5.3, which is strongly acidic. Acidic soils benefit from lime applications to raise pH and improve nutrient availability.
What is the drainage class for Island County?
Drainage class data is not currently available for Island County.
What crops or plants grow well in Island County's soil?
Based on Island County's Sandy Loam texture, pH of 5.3, 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 Island County?
The dominant USDA soil order for Island County is not currently available in our dataset.
Soil & Planting Advisory: Island County
Soil Verdict
Island County is in USDA hardiness zone 8b, a warm climate zone. where winter lows can reach 15°F. Mild winters mean soil rarely freezes deeply, allowing year-round microbial activity and faster organic matter breakdown.
Planting Guidance
Warm-season crops, citrus relatives, and heat-loving ornamentals do well. Cool-season vegetables should be planted in fall and winter. 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
Warm soils accelerate organic matter breakdown, so compost and mulch need replenishing more frequently than in cooler zones. Sandy soils common in warm zones drain quickly; water-retentive amendments like compost or peat help hold moisture.
Regional Context
Island County is somewhat warmer than the Washington statewide average.
Planning your lawn? View lawn care data for Island 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.