Hydroponics is the technique of growing plants without soil, but rather in beds of sand, gravel, or artificial mediums that are flooded with a nutrient solution.
Basically a simple hydroponics system consists of a pot, a reservoir, a grow medium, a pump and a set of growth nutrients. The system itself has a top layer and a lower layer. The top layer holds the grow medium and the bottom layer holds the water with added nutrients. The plant is grown in the medium where it will develop a stem and a set of roots. The roots will grow through the medium and down into the nutrient solution. Water and nutrients are pumped into the lower portion of the tank through a reservoir at certain timed intervals. The plants drink the solution down and thus expose their roots to the air more. If this it timed correctly and the growing solution is maintained the plants will flourish! This is because the plant can devote more of its energy into upper-body growth rather than putting that energy into roots searching for water and air. Now having said this, hydroponics produce massive root clusters and I mean a big mass of roots. One can easily pick up a 2-gallon bucket full of root growth from a single plant! This is because roots thrive in hydroponics systems.
Hydroponics, when done correctly, can produce a flowering plant up to 3/4 the normal time that it would take with a soil grow. That is right! Hydroponics can grow bigger and better buds in 3/4 the time it takes to grow the same strain in soil.