What is Sandy Loam Soil ? ... Soil type is best determined by a soil test, but for the home gardener this is not always feasible. Observing soil properties is generally sufficient to determine its type. Sandy loam soil is a mixture of sand, silt and clay in roughly even proportions. Sand, silt and clay are defined by different particle types in soil identification. When dry sandy loam soil will form into a solid clump that readily crumbles when touched. When wet, it forms a crumbly ball and will hold some finger indentations if squeezed.