Different Types of Hydroponic Systems

Prof Gert Venter explains the benefits of a static hydroponic system, which can be grouped into ‘open’ or ‘closed’ categories, and broadly subdivided into three main groups: static, dynamic and aero systems.

- Prof Gert Venter

Hydroponic systems can be categorised as either ‘open’ or ‘closed’ types. In the former, the nutrient solution is fed to the plant roots, but excess water and nutrients are lost due to drainage or seepage into the ground. The nutrient solution in a closed system, on the other hand, is circulated in a closed loop to be reused repeatedly.

Closed systems require less water and fertiliser than open hydroponic systems, but need slightly more inputs from the grower. The nutrient solution has to be replenished from time to time, as well as purified to prevent the build-up of disease.

It is also necessary to adjust the chemical content of the nutrient solution periodically, to ensure that the various chemical elements are kept in balance to meet the plant’s requirements for optimal growth.

The various kinds of hydroponic systems can be broadly subdivided into three main groups: static, dynamic and aero systems, including aeroponics.

STATIC AERATION TECHNIQUE (SAT)

Most children become acquainted with SAT hydroponics at school when they are shown how to suspend an avocado or mango pip above water in an open bottle or other container to study the basics of plant growth. They are often amazed to see how roots start to develop and grow into the water, with a little shoot then starting to sprout.