Hydroponic farming is a method of growing plants, usually crops or medicinal plants, without soil, by using water-based mineral nutrient solutions. Instead of growing in soil, plants are grown in a water-based nutrient solution or an aggregate substrate, such as vermiculite, coconut coir, or perlite. Hydroponic production systems are used by small farmers, hobbyists, and commercial enterprises. Plants commonly grown hydroponically include tomatoes, peppers, cucumbers, strawberries, lettuces, and cannabis, usually for commercial use, as well as Arabidopsis thaliana, which serves as a model organism in plant science and genetics. Hydroponic cultures lead to the highest biomass and protein production compared to other growth substrates, of plants cultivated in the same environmental conditions and supplied with equal amounts of nutrients.

Hydroponic farming has several advantages over traditional soil-based farming. For example, hydroponic growing takes much less water and nutrients to grow produce, and climate change threatens agricultural yields, so it could be possible in the future for people in harsh environments with little accessible water to hydroponically grow their own plant-based food. Plants grown in well-managed hydroponic systems are living the good life. Since roots are bathed in all the nutrients they need, plants spend more time growing upward and less time and energy growing extensive root systems to search for food. Hydroponic farming has the potential to provide fresh, local food for areas with extreme droughts and low soil quality, such as in sub-Saharan Africa where access to leafy green vegetables is often limited.

Hydroponic farming is not a new concept and has been used by physiologists studying plant nutrition and by other plant scientists for more than a century. Many different civilizations have utilized hydroponic growing techniques. There are multiple approaches to designing hydroponic systems, but the core elements are essentially the same.