ABSTRACT
Hydroponic crop production refers to the growing of crops in solutions of plant nutrient-containing salts dissolved in water. Soil is not involved in crop production in hydroponics although solid, inert media are used in many hydroponic systems. Water-culture is a system of hydroponics in which crops are grown in water with little or no solid medium to hold the plants in place. Some people argue that water culture is true hydroponics and that crop production in solid media with hydroponic solutions is soilless culture. People should understand that crops can be grown hydroponically in practices that use a solid, inert, soil-free medium to hold the crops in place. In this case, the medium supplies no nutrients to the crops, and the nutrient solution is the same as that used in water culture and is held in the pore space of the medium. The nutrient solution is supplied to the medium as necessary to provide water and nutrients to the crops. In hydroponics, it is important that the solid medium is chemically inert and resistant to microbial action so that crop nutrition is controlled by the nutrient solution.
