Hydroponics is the method of growing plants without soil by supplying them with a constant nutrient solution. Despite the fact that this method remains fairly unknown outside of a small sector of the horticultural world it has in fact been around for a long time. It is a system that was used extensively in the hanging gardens of Babylon and has been studied extensively by scientists and horticulturists for the last several hundred years. Hydropolics allows for a very precisely controlled amount of nutrients, dissolved in water, to be administered directly to the root system as the plant requires it. There are a variety of variations on the hydroponic theme and this book will take a look at the main options the gardener has available to them.