Hydroponics

Hydroponics, or soil-less culture, technique by which plants are grown without soil. All the minerals required for plant growth are provided by nutrient solutions in which the roots are immersed. The technique has been highly developed as a tool in botanical research, but commercial exploitation is limited primarily because of the difficulty of aerating the water and providing support for the plants. Gravel culture has overcome these problems to some extent and is used to grow some horticulture crops.