St. Helena Parish Soil Data
St. Helena Parish, Louisiana
USDA SSURGO / PHZMAvg pH
5.2
Texture
Silt Loam
Drainage
N/A
Organic Matter
2.6%
Hydrologic Group
N/A
Data Story
About Soil in St. Helena Parish, Louisiana
Strongly Acidic Upland Soils
St. Helena Parish has a very acidic soil pH of 5.17, which is notably lower than the state average of 5.74. This level of acidity can limit the availability of phosphorus and calcium for many garden plants. Lime is almost always required to bring these soils closer to the national median of 6.5.
Silt-Heavy with Moderate Sand
The soil contains 50.7% silt and 35.9% sand, with a low clay percentage of 13.4%. This combination produces a medium texture that is easy to cultivate and provides good aeration for roots. It avoids the heavy, sticky nature of clay-rich soils found further south.
Reliable Water and Organic Content
Organic matter sits at 2.55%, which is healthy compared to the national average of 2.0% but lower than the state's 6.38%. The available water capacity of 0.184 in/in is right at the state average. This indicates the soil has a solid ability to support crops through typical dry spells.
Standard Infiltration Patterns
Specific drainage and hydrologic data are unavailable for this parish, but the silt-sand mix suggests moderate drainage. Without a high clay content, water should move relatively freely through the upper soil layers. Monitoring local slopes is still important to prevent erosion in these silty profiles.
Versatile Gardening in Zone 9a
Zone 9a provides a long growing season for everything from sweet potatoes to blueberries. Because the soil is naturally quite acidic, it is perfect for acid-loving shrubs like camellias and azaleas. Grab a soil test kit and start your garden journey in this warm, productive climate.
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 5.2. These products help balance soil pH for healthier grass.
Browse Soil AmendmentsFrequently Asked Questions
What type of soil does St. Helena Parish have?
St. Helena Parish's soil is classified as Silt Loam. This indicates the relative proportions of sand, silt, and clay — 36% sand, 51% silt, and 13% clay. Loamy soils hold moisture well and support a wide range of plants.
Is St. Helena Parish's soil acidic or alkaline?
St. Helena Parish's soil has a low pH of 5.2, which is strongly acidic. Acidic soils benefit from lime applications to raise pH and improve nutrient availability.
What is the drainage class for St. Helena Parish?
Drainage class data is not currently available for St. Helena Parish.
What crops or plants grow well in St. Helena Parish's soil?
Based on St. Helena Parish's Silt Loam texture, pH of 5.2, 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 St. Helena Parish?
The dominant USDA soil order for St. Helena Parish is not currently available in our dataset.
Soil & Planting Advisory: St. Helena Parish
Soil Verdict
St. Helena Parish is in USDA hardiness zone 9a, a warm climate zone. where winter lows can reach 20°F. Warm winters keep soil biology active nearly year-round, accelerating decomposition but increasing pest and disease pressure in topsoil.
Planting Guidance
Tropical and subtropical plants are viable. Year-round gardening is possible, though summer heat may limit some cool-season crops. Frost is rare; tender plants can overwinter with minimal 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
Rapid organic matter turnover means soils can become nutrient-poor quickly; test annually and fertilize based on results. High soil temperatures favor certain soilborne pathogens; practice crop rotation and avoid overwatering.
Regional Context
St. Helena Parish closely matches the Louisiana average hardiness conditions.
Planning your lawn? View lawn care data for St. Helena Parish on LawnByCounty.com →
Other Counties in Louisiana
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.