is a method of growing plants without the use of soil. There are two main categories of hydroponic growing: liquid and aggregate. The liquid method uses no growing medium; the plant is merely suspended over the nutrient solution so that its roots may absorb the needed elements. The aggregate system has the plant supported by a sterile, solid yet porous growing medium, but again the roots are bathed with a nutrient solution to provide their nutritional needs. All of the nutrients that the plant will require to grow are provided for in the ....