Understanding Semi-Hydroponic Systems

Prof Gert Venter explains the benefits and disadvantages of semi-hydroponic structures.

- Prof Gert Venter

Semi-hydroponic systems are often referred to as passive sub-irrigation hydroponics. I prefer to refer to this group of hydroponic systems as capillary hydroponics, which better describes what it entails.

Capillary hydroponics is a method whereby plants are grown with their roots in contact with an inert porous medium or polymer film that transports the nutrient solution by capillary action to the plant root zones from a separate reservoir nearby. This system provides the plant roots with a continuous supply of water and nutrients without the assistance of a pump, thus reducing the labour involved.

WICK SYSTEM

The simplest capillary system is the so-called wick system, which has no moving parts or pumps, and requires no external energy or electricity for its operation. It is useful for small-scale and low-cost hydroponic applications in areas where power is too expensive, unreliable or not available at all.

A wick hydroponic system is easy to build and operate, and is often used by beginners starting out with hydroponics. The system can also be used to introduce learners to hydroponics by demonstrating how easy it is to grow plants hydroponically.

To build your own wick hydroponic system you will need:

A container for the plant;

A container or reservoir for the nutrient solution;

A suitable substrate or growth medium, such as fine sand, sawdust, cocoa coir, vermiculite or perlite;