A plant needs light, water, nutrients, and oxygen to grow. The Kratky method provides all this in a very simple way. You add water with all the mineral solution needed into a container with a net pot and some rock wool (or a growing medium of your choice), plant your seed and let it grow.
Dr. Bernard Kratky's American Society for Horticultural Science horticultural talk on non-circulating hydroponics. Graduate of Purdue University and professor in Hawaii, Dr. Kratky's patented methods are known around the world.