Different plant soils are categorized based on their texture, such as particle size and how they feel between the fingertips, and on whether or not they provide good drainage. Different soil types are prominent in different regions and knowing the type of soil you are working with is essential to successful plant growth as plants need particular conditions for proper water and nutrient absorption.
Sand Plant Soil
Sand or "sandy" soils refer to a type of texture. Sands exist in a very loose-grained state and do not have the ability to compound whether in moist or dry conditions. With large particles that can be seen by the human eye, this type of plant soil feels coarse to the touch and crumbles easily. Moisture effortlessly flows through sand but absorption is low. Based on the USDA soil textural triangle, sand plant soil has at least 85 percent sand-sized particles, up to 15 percent of silt-sized particles and up to 10 percent of clay-sized particles, according to the University of Florida IFAS Extension. Sandy soils tend to have lower organic content and are suitable for plants tolerant of drought with deep roots.
Loam Plant Soil
Loam plant soil consists of a medium texture with a variety of particle sizes that are loose-grained and appear loose to the eye. Moist loam soil may be formed into a compact ball but crumbles upon heavy contact. Loam includes sand, silt and clay soil types; this mixture has a gritty texture and feels soft to the touch. This type of soil absorbs and stores water well in varying degrees based on the amount of each soil component. A sandier loam, for instance, absorbs less water than one higher in clay. Since loam is a combination of soil types, USDA texture percentages vary. Due to loam's "middle of the road" properties with medium texture and satisfactory drainage, loam is considered the more versatile plant soil for a wide variety of plants.
Clay and Silt Plant Soil
Clay and silt plant soil types exhibit a fine texture due to their fine particle size. These types of soil compact easily and will form a tight ball if squeezed in one's fist. Highly water absorbent, these soils feel smooth and become sticky when saturated with water. Due to absorbency, clay and silt compacts easily and creates decreased drainage for plants as water cannot move through the particles. Water often collects on the surface of clay or silt soil, according to the City of Bremerton, Washington. These fine textures are generally higher in fertile and organic content, making them more nutrient dense; however, due to poor drainage, you should grow plants that thrive in poor drainage conditions. To improve drainage, add organic amendments to alter the structure of your soil. Adding organic content such as manure or compost decreases the compaction of clay soil for better drainage. Depending on the amount of soil you need, an amendment addition equaling up to half of the volume of your soil may be necessary. Determine the proper amendment to soil ratio by beginning with a plant pot filled with the initial soil and amend the clay until drainage is satisfactory.