What is the practice of growing plants in water without soil?

The practice of growing plants in water without soil is called hydroponics.

In hydroponic systems, plant roots receive water containing dissolved mineral nutrients. The roots may grow directly in the solution or be supported by an inert medium such as perlite, gravel, rockwool, or expanded clay. Soil is not required because its main relevant functions—holding roots, water, air, and nutrients—can be supplied through controlled equipment.

The idea has a long scientific history. Francis Bacon described experiments with soil-free plant growth in his 1627 book Sylva Sylvarum. John Woodward published water-culture experiments with spearmint in 1699, and later researchers such as Julius von Sachs and Wilhelm Knop helped establish nutrient-solution methods. William Frederick Gericke popularized the word “hydroponics” for agricultural production in the 1930s.

Hydroponics is often confused with aquaponics, which combines fish farming with plant cultivation, and aeroponics, which suspends roots in air and mist. Hydroponic crops commonly include lettuce, tomatoes, peppers, cucumbers, and strawberries.