Hydroponics is a cultivation technique that grows plants without soil. It involves a grow-bed container filled with chemically inert media like sand or rockwool that holds the plant's roots. Below the media is a nutrient reservoir that feeds a specially formulated hydroponic solution into the grow bed through a wick system, relying on capillary action and media absorbency to water the plants. While hydroponic nutrients are usually chemical-based, some groups have developed organic soilless systems that use natural materials.