Hydroponics is a subset of hydroculture, which describes growing plants with a water-based mineral nutrient solution and without soil. There are many different types of hydroponic systems although the core elements are similar, with the roots being supported in various types of media such as coco coir, perlite, gravel, or another substrate.
With hydroponic growing, plants do not get any of the nutrients naturally found in soil, and all nutrients must be provided through a liquid solution. This gives the grower total control, although it is critical to maintain the right environment and check pH and nutrient levels regularly.
Some of the benefits of growing weed with hydroponics are that you are not as prone to attracting pests compared to growing outdoors in soil, some systems are easy to set up, and are space efficient. Maintaining a Hydro system does require an investment of time on the part of the grower to maintain healthy plants. The most common thing that goes wrong with the hydroponic system is a lack of water for even a short period of time or even a slight change in pH levels which can set back plant development or destroy the entire crop since all plants are maintained with the same water and nutrient solution.
Beginning growers setting up a hydroponic system are better to start with a simpler system and not a lot of plants until they get used to maintaining a healthy hydroponic system.