So that’s how it works . . . learning about aquaponics in Jerusalem

THE NATURAL resources of the earth are slowly diminishing due to natural and forced changes in the atmosphere. At the same time the human population is increasing at a fairly quick rate. In order for the human race to survive, each individual must have a minimum amount of food which is becoming harder and harder to supply. To date the attempted answer was or is by using high technology to force the natural resources to supply larger amounts of food. In a constant battle of the human brain against nature – chemical sprays against insects, genetically modified seeds, computerized hothouses are being used to increase the yields of edible crops. Wait a minute. We are so into our brilliant high-tec solutions that we never ask the question: Maybe the soluction for the future is in the past? Why fight nature? Maybe working with her in partnership might be the solution? That is what aquaponics is all about. Why try to reinvent? Why not just copy a proven system and make it more efficient? A natural waterway eco-system is an effective growing method for food production so if we set up something similar in an artificial surrounding which is a closed circuit recycling water and soilless growing beds we would be saving two vital resources – water and soil. Great but how does this work? It’s a mixture of two known systems: hydroponics – soilless vegetable growing – and fish farming joined together via a closed water recirculating system. Water is recirculated from a tank or pond populated with fish to a growing bed of Styrofoam floating on water and gravel or volcanic stone (tuf) with water running through them in which the vegetables are planted. But plants cannot survive on water alone. So nature has provided us with a nitrogen cycle which is the be-all and end-all of the aquaponic system and is responsible for converting fish waste into nutrition for the vegetables whose roots and microbes in turn filter the water before it returns to the fish tank. This ensures that the water does not become toxic which is dangerous for both fish and plants, thus the water does not have to be chemically treated for it to be “safe”. In aquaponics a system is said to have cycled when there are sufficient bacteria to convert the fish excretion (ammonia) into an accessible form of nitrogen for the plants (nitrates). So what have we achieved? An environmentally friendly system with the only unnatural element being the electricity to run the water pump. We can set up an electrical solar system (expensive) and be totally independent of artificial elements. Aquaponics uses about 85-90% less water than vegetables grown in soil. Because of the direct supply of nutrients we can plant the vegetables closer to each other thus growing more per square meter than in soil. In various tests the vegetables in the aquaponic system have a shorter growth period than in soil. So we are saving space, saving water, saving soil and time. If we are totally committed to being environmentally friendly we will recycle all materials such as wood, plastic pipes, old barrels for fish ponds, to build the fish tanks and growing beds and, just to put the cherry on the cake, a worm farm to recycle organic waste from the kitchen and the garden.

Health? No chemicals whatsoever, pure organic vegetables. Let’s not forget the commercial aspect of getting two products for the price of one: fish and vegetables.Basically any fresh water fish can be used. If you are a vegetarian then garden fish such as goldfish, but if you are not “yummy”, depending on the weather in warmer climates, most growers use Tilapia or any other warm water fish if not cold water fish such as trout or carp. Any vegetable can be grown in the system provided that the growing base is suitable. For example on Styrofoam floating on the water we would grow lettuce, spices and vegetables which are lighter in weight and whose leaves are edible. If rooted vegetables such as radish, onions, or potatoes it would be too heavy thus a gravel or tuf base would be used.

The concept of using fish waste to fertilize plants according to some historians existed for centuries with early civilizations both in Asia and South America.   In the 1980s it became a viable food production system which led to the creation of closed systems which recycle   water.   To date there are thousands if not tens of thousands of hobbyists throughout the world as well as universities and a smattering of commercial enterprises experimenting   and making the system more efficient.   So to conclude, if you want to join the fun we'll be happy to be of help.

 

A simple aquaponic system fish tank grow bed

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About the author

Shalom Brenner

Shalom Brenner, originally from a farm in Upington, South Africa, came to live in Israel in 1962. He completed his Accountancy studies at Haifa University in 1972.

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