Nutrient solutions intended for plant growth are already used from the middle of the 19th century, when the importance of mineral elements for plant growth was made clear by Justus von Liebig. In advance, the nutrient solutions used to grow plants in so called “water cultures” had a simple composition and consisted of salts like KNO3, Ca(NO3)2, KHPO4, MgSO4, and a little Fe-compound (Hoagland and Arnon, 1950), thus, containing all the major elements and some Fe. The relative success with these solutions will be due to the not knowingly supplied micro nutrients from the impurities of the chemicals and fertilizers used to compose the solutions. It can be supposed that the impurities contained sufficient micronutrients, to prevent the crops grown from serious nutrient disorders. Knowledge about the necessity of micro nutrients for plant growth was mainly gathered in the first half of the 20th century (Marschner, 1997), when the purification of fertilizers and chemicals were improved. The first systematic description for the preparation of nutrient solutions was given by Hoagland and Arnon (1950) and since then in many publications reference is given to them, when one or another nutrient solution is used to grow plants in soilless cultivation systems.