Hydroponics is where the fruit and vegetables sit on troughs with their roots dangling in a water based solution containing the necessary minerals and nutrients required for growth.
As it is through their roots that plants take up nutrients this is an efficient growing system.
There are both closed and open systems; in the closed system, there is a cover over the top of the trough and the water solution is recycled.
A high degree of automation is possible with this system, making it popular with mass producers of luxury salads and vegetable plants.
It is also a suitable form of cultivation in areas with low rainfall as due to the recycling of the solution water used is very efficient.