Potting Soil Characteristics

• Potting soil provides the plant with physical and nutritional support. The soil must retain moisture while draining well. Depending on its dedicated purpose, potting soil may contain materials providing essential minerals and nutrients. Potting mixes for most orchids provide little nutritional support and are not suited for many other species of potted plants. Mixtures for growing cacti typically contain up to 50 percent sand.
  
  

Essential Components

• Most potting soil mixes contain peat moss, shredded bark and perlite or vermiculite. Peat moss and shredded bark slowly decompose releasing organic nutrients the plant uses. Perlite and vermiculite are both mineral additives capable of retaining moisture and providing drainage for the soil.
  
  

Nutritional Additives

• Since potted plants are not able to absorb nutrients from the earth, supply them with essential minerals and nutrients. In addition to essential components, many potting soils contain composted manure products. Manufactured plant-food pellets are added to some potting-soil varieties.
  
  

Rehydration

• To rehydrate dried potting soil, pour the soil into a large container, such as a wheelbarrow or bucket. Add water a little at a time and mix it thoroughly with your hands or a garden spade. Continue adding water and mixing until a handful of the potting soil holds together when squeezed.