Back to Course Home


To be able to understand Aquaponics, one needs to understand the concepts of hydroponics very well.

Hydroponics is by no means a new concept. Plant scientist from the beginning of time have been curious to know what composes plants. In other words, what makes a plant grow?

All living things have physical needs that must be met in order to sustain life. Plants require certain elements to develop, reproduce, and survive. Plants need room to grow, the correct temperature, sunlight, water, air, and a combination of nutrients. A lack of these requirements can inhibit the plants growth.

Soil function mainly as support to a plant and help to supply nutrients to the roots of the plant.

Hydroponics is a technique for growing plants without using soil. Utilizing this technology, the roots absorb a balanced nutrient solution dissolved in water that meets all the plants developmental requirements.

It is believed that John Woodward, in England, first unwittingly started the science of hydroponics. This was in 1699. Many plant experiments were probably been done even before this time. Woodward cultivated plants in water to which he added different types of garden soil. He thereby showed that certain substances derived from earth, rather than water itself, were responsible for plant growth.  

There is nothing better for growing plants than a first-class soil. But what makes such a soil? Among many qualities, a good soil must have a balanced supply of available plant nutrients. Many soils entirely lack one or more of the essential nutrient elements. Take phosphorus for example: This has often to be supplied to the soil in the form of a fertilizer application of superphosphate. Similarly potassium sulphate is used for potassium deficiency, ammonium sulphate, nitrate, or urea for nitrogen deficiency, and so on. In the hydroponic method, a balanced diet of plant nutrients is constantly available. There is therefore no need to fertilize.

The advantages of hydroponics:

  • No need to fertilize
  • No cultivation activities needed (digging, raking or hoeing)
  • No crop rotation needed
  • Virtually no weeds
  • A tendency towards uniform growth results
  • Cleanliness and bio-security
  • Larger yields
  • Less labor intensive
  • Better environmental control possible
  • Ease of starting off new seedlings or plants
  • A means of upgrading or revitalizing poor growing plants from marginal soils

Research has determined that many different aggregates or media can support plant growth, therefore, the definition of hydroponics has been broadened to “the cultivation of plants without soil.”

Picture 1: NFT system at Greendrop hydroponics farm outside Stellenbosch, South Africa.