Soil Texture (Fine or Coarse) Hold a little bit of soil in between your thumb and forefinger. A gritty feel means there is a lot of sand in the soil, while a slippery soil means that there is a lot of clay, and silt feels kind of greasy. All soil has each of these three components in varying amounts, and they are each a necessary part of soil composition. Minerals and nutrients in the soil are where plants get most of their nourishment. Soil texture affects how easy it is for plants to get nutrients from the soil. A soil with good texture has equal amounts of sand and silt, about 40 percent each, and a lesser amount of clay, about 20 percent. This type of soil is called a loam, and it allows good drainage and root growth, yet retains adequate moisture and is rich in nutrients.
Soil Structure (Loose or Clumping) Look at your soil to see if it is grainy or if it forms clumps, like clay. Soils that are too loose and do not hold together do not hold nutrients and moisture that plants need, so plants are weak. Soils that clump do not allow plant roots to move freely or take hold properly, so plants are small. Good soil structure is a little grainy and clumps loosely to allow good drainage, but retains moisture and nutrients that plants can use.
Soil Nutrients The three main nutrients that plants get from soil are nitrogen, phosphorus and potassium. Nitrogen makes big, beautiful leaves. Phosphorus helps growth and makes strong root systems and big, attractive flowers. Potassium builds protein, helps in the photosynthesis process and fights disease. Adding organic plant matter to the soil, in the form of compost, adds nutrients plants need and improves soil structure and texture.