ABOUT HYDROPONICS: Hydroponics is a method by which plants can be grown in water without any soil. Growers place plants in nutrient-rich mineral solutions and can choose to add an inert medium such as gravel, coconut husks, or mineral wool. It was discovered in the 18th century that plants absorb essential mineral nutrients via inorganic ions in water, and that the soil itself is not essential to plant growth but acts as a nutrient reservoir. Plant roots are able to absorb the nutrients once they dissolve in the water. Many terrestrial plants can be grown using hydroponics.