It is believed that one of the ancient wonders of the world – The Hanging Gardens
of Babylon were actually based on Hydroponics
The modern version of an ancient concept
Literal translation from Greek -
Hydro = Water & Ponos = Working
Now an intensive way of farming without soil.
Some of the main strengths:
No need to fertilise fields
No need for expensive mechanical implements to work the soil – Lower Carbon Footprint
No need to rotate crops
More effective disease control
No soil borne pests and diseases
Virtually no weeds
Tendency towards uniform results
Crops are grown in a controlled environment
Larger yields – up to 100 x Field-Yield
Less vulnerable to adverse climatic conditions
Vastly reduced water consumption < 10%
Better control over the plant growth
Some of the weaknesses:
High start-up costs (relative)
Requires specialised knowledge to operate
Dependent on reliable electricity source
In severe storms the greenhouses may get damaged-instead of just the crop. But-
There are engineering innovations to minimize these risks.
Types of Hydroponic technology
Gravel Nutrient Film (GFT) Crops are ‘planted’ into shallow layers of gravel. The gravel
holds the roots and prevents evaporation.
Deep-Water/Raft Systems Crops grown at high density in “rafts” floating in tanks of
Nutrient Film Technology
Crops are ‘planted’ into plastic ‘channels’ of gutters where the roots hang freely
in a shallow layer of water.
Why the necessity and urgency to introduce
Hydroponics into the mainstream food
Production in Africa?
With the dwindling water resources, vast areas of in arable land and persistent adverse
weather conditions, added to rapid population growth and urbanisation.......
Africa as a whole is fast losing the battle to maintain Food Security.
Only sophisticated Agricultural Production methods can address that problem!
The various Hydroponics and Greenhouses are designed to use water as efficiently as
For, up to 100 times the field-yield on certain crops, less than 10% of the water
usage is needed.
Only the water absorbed by the plants is used. Water – saving features:
No dissipation of water into surroundings
Drastically reduced evaporation losses
Water is continuously re-cycled & re-used
Evaporated water can be condensed inside the greenhouse and sent back into the system.
Electricity & Energy – saving features:
Gravity feed the systems
Solar Panels can provide sufficient power to operate the systems.
LED and DC systems avoid inverter losses
Solar heating and thermal ballast is used
Natural ventilation and cooling methods are used where possible
The next logical step in technology, also with ancient roots.
It is said that the ancient roots of Aquaponics were in China, when rice farmers
noticed that there was in improvement in their crop performance when there were Carp
or Catfish present in their irrigation canals.
It took many centuries, and only relatively recently was there a handful of practitioners
and scientists who explored the subject, and started quantifying it to begin the
commercial use of this ancient practise.
Aquaponics is the combination of Aquaculture and Hydroponics, in a symbiotic relationship.
The effluent from the fish production part, is a perfect source of fertilizer for
the plant production part, and the plant production is an efficient filtration system.
The technical reality of commercially exploiting this rather ‘simple’ system is far
more complex than one would like to believe. Even though there are many enthusiasts
whose systems have produced very well, without the sound understanding to the principles
and the science behind it, the successes are likely to be erratic, and the systems
do not run at their full potential.
Brief explanation of the concept.
Aquatic animal effluent (for example fish waste) accumulates in water as a by-product
of keeping them in a closed system or tank (for example a re-circulating aquaculture
system).The effluent rich water becomes high in plant nutrients but this is correspondingly
toxic to the aquatic animal.
Plants are grown in a way (for example a hydroponic system) that enables them to
utilize the nutrient rich water. The plants absorb the nutrients, reducing or eliminating
the water’s toxicity for the aquatic animals.
The water now clean is returned to the aquatic animal environment and the cycle continues.
Aquaponic systems do not discharge or exchange water. The systems rely on the natural
relationship between the aquatic animals and the plants to maintain the environment.
Water is only added to replace water loss from absorption by the plants or evaporation
into the air.