St. Martin Parish Soil Data
St. Martin Parish, Louisiana
USDA SSURGO / PHZMAvg pH
6.1
Texture
Silty Clay Loam
Drainage
N/A
Organic Matter
3.1%
Hydrologic Group
N/A
Data Story
About Soil in St. Martin Parish, Louisiana
St. Martin's Balanced Acidic Profile
The parish maintains a pH of 6.10, sitting closer to the national median of 6.5 than most of Louisiana. This makes the soil less acidic than the state average of 5.74, reducing the need for heavy lime applications.
A Silty Mix with Clay Body
Composition consists of 54.4% silt and 33.7% clay, making it a dense and moisture-retentive medium. With only 10.6% sand, these soils are naturally fertile but require careful timing for tilling.
Strong Organic Content for Crops
Organic matter is healthy at 3.15%, well above the national average of 2.0%. Combined with an available water capacity of 0.186 in/in, these soils provide a stable reservoir of nutrients and moisture for local agriculture.
High Clay Leads to Slow Drainage
The 33.7% clay content indicates that water moves slowly through these soils compared to sandier parishes. Proper grading is essential for residential building to prevent ponding in backyards.
Grow Year-Round in Zone 9a
The mild climate of zone 9a and a soil score of 64.1 create a highly productive environment for citrus and sugarcane. Grab some seeds and take advantage of this above-average Louisiana soil.
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: Silty Clay Loam
Typical soil profile. Actual depths vary by location.
USDA Soil Orders
Clay Soil Detected
Clay soils can struggle with drainage. These products improve soil structure and water flow.
Browse Soil AmendmentsFrequently Asked Questions
What type of soil does St. Martin Parish have?
St. Martin Parish's soil is classified as Silty Clay Loam. This indicates the relative proportions of sand, silt, and clay — 11% sand, 54% silt, and 34% clay. Loamy soils hold moisture well and support a wide range of plants.
Is St. Martin Parish's soil acidic or alkaline?
St. Martin Parish's soil has a pH of 6.1, which is moderately acidic. This range suits many crops and is common across much of the eastern US.
What is the drainage class for St. Martin Parish?
Drainage class data is not currently available for St. Martin Parish.
What crops or plants grow well in St. Martin Parish's soil?
Based on St. Martin Parish's Silty Clay Loam texture, pH of 6.1, 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 St. Martin Parish?
The dominant USDA soil order for St. Martin Parish is not currently available in our dataset.
Soil & Planting Advisory: St. Martin Parish
Soil Verdict
St. Martin 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. Martin Parish closely matches the Louisiana average hardiness conditions.
Planning your lawn? View lawn care data for St. Martin 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.