Abstract: A hydroponic growth medium in the form of a disposable tubular fibrous element. The tubular element consists of axially oriented internal fibers to provide good capillary or wicking properties to the element, and a shell surrounding the fibers to provide some structural integrity to the element. The element is of a cross-sectional area at one end that is sufficient to provide a satisfactory seat for a seed. In use, the disposable element is oriented in a generally vertical position, and a seed is placed on the seat defined by the element's top end surface. The element's bottom end is immersed in a nutrient solution, which is then continuously fed to the seed through the capillary action provided by the axially aligned fibers within the element. As the seed grows into a plant, the element's shell directs or controls the plant's root growth so that the roots proceed generally axially and downwardly through the element, rather than simply growing outwardly in random fashion through the element's side walls.