he science of hydroponics proves that soil isnt required for plant growth but the elements, minerals and nutrients that soil contains are. Soil is simply the holder of the nutrients, a place where the plant roots traditionally live and a base of support for the plant structure. In hydroponics you provide the exact nutrients your plants need, so they can develop and grow. The nutrients are fed directly at the root base, never stressing the plant due to lack of nutrients or water.

Website: http://www.hydroponicsonline.com/lessons/table-of-contents.htm