Water and carbon are needed for photosynthesis, but soil is not.
Photosynthesis is the process by which plants use the energy from sunlight to convert water and carbon dioxide into oxygen and organic compounds such as glucose. The process involves the absorption of light energy by chlorophyll molecules, which are found in the chloroplasts of plant cells. Water is used by the plant as a source of electrons and hydrogen ions, while carbon dioxide is used as a source of carbon. Soil is not necessary for photosynthesis, although it does provide essential nutrients for the plant.