ABSTRACT
A number of nutrient solutions have been developed for hydroponic cultures, such as the Hoagland, Sach’s, Knop’s, Pfeffer’s, and Crone’s solutions (Jones, Jr., 1983; Douglas, 1976; Hewitt, 1966; Hoagland and Arnon, 1950). One of the nutrient solutions frequently used in the United States is the so-called Hoagland and Arnon solution, often called the Hoagland solution, which has a composition as listed in Table 9.1. According to general opinion, the other types of nutrient solutions are
equally as effective for water cultures as the Hoagland solution. As correctly indicated by Hoagland and Arnon (1950), there is no one composition superior to another. Plants are assumed to be able to adapt remarkably to different chemical environments; otherwise they would not be growing in all kinds of soils in nature. This opinion is somewhat confusing, since many of the other nutrient solutions carry
relatively less nitrogen than the Hoagland’s, as shown in Table 9.1 for 2the Knop’s nutrient solution, and yet N is an essential nutrient
element for plant growth.
