Hydroponics is a means of growing plants in nutrient water without the use of soil. Instead of soil a non-reacting medium is used such as perlite, gravel, or the husk of coconuts. It was known as early as the 18 century that plants absorb their minerals in water as ions. The soil in traditional growing acts as a nutrient reservoir but does not actually contribute to plants growth. Water dissolves the minerals in the plants soil enabling the plants to use them. In hydroponics the minerals required for plants growth are artificially dissolved in the water making soil unnecessary. It is possible to grow almost any soil based plant using hydroponics. Hydroponics is such a promising field that there is much research into different methods in the academic community.