All plants require essential nutrients for healthy growth. There are in total seventeen different elements that make up these essential nutrients. Three of these elements: carbon, hydrogen and oxygen are absorbed from the air whereas the other fourteen elements are usually obtained from the soil. The soil-less growing media such as bagasse, sawdust, coconut coir and rice hulls, typically used in grow boxes have little or no nutrients therefore, plants growing in these media types will need to be supplied with fertilizers to meet their nutritional requirements. Nutrients from air and water Carbon (C) Plants absorb carbon from carbon dioxide (C O 2 ) in the atmosphere. Hydrogen (H) Hydrogen is obtained from water ( H 2 O) which is absorbed by the plant roots. Oxygen (O) Oxygen comes from gaseous oxygen ( O 2 ) and carbon dioxide (C O 2 ) in the atmosphere. Nutrients from the growing medium The nutrients that your plants require from their growi...