Just so you know, we make and sell DVDs on Aquaponics with Aquaponics guru Murray Hallam. But this isnt a sales pitch. I don't care if you buy one of our DVDs or not. The truth is a couple of years ago I got interested in Aquaponics and wanted to know more. I was never very good at keeping fish. Well I did keep a goldfish in a bowl for almost a year that lived in very dirty water. One day I had an idea to change its water - and it promptly died. Thats another story. So I was your average person with really no interest in keeping fish in the backyard.

But I was interested in growing vegetables with them.

Our backyard is right next to the beach. We live on a sand dune. The soil is very, very white. A few years ago sand mining companies wanted to mine it. Its first class silica sand. Good for making computer parts. Bad for making vegetables. Yeah, we tried putting manure and chicken poo on our vegetable patch and it does work - for a while. But eventually the nutrients wash away. Goodbye soil fertility. Hello sad looking vegetables.

Fast forward to Yandina Permaculure Gardens a year later. Guest speaker is Mr Murray Hallam who makes fibreglass kit troughs for Aquaponics. I met him after his talk and we got on like a house on fire. He's a great bloke. When my wife Jane and I saw his aquaponics garden - we were hooked. He had cabbages and strawberrys growing like gangbusters! He had a mighty looking pawpaw tree reaching into the top of his greenhouse - loaded with fruit. Was he using chemicals? Nope! He had all sorts of herbs cascading down around his growbeds. Nothing looked like it was struggling. The plants looked terrific.

I wanted what he had. As we drove home I convinced Jane why it was a good idea. Firstly - no bending and no digging. No weeding. No bad backs. Everything at waist level. Secondly No Soil! That might scare you - but I thought it was a terrific idea. No dirt under your fingernails and lets face it - all those red coloured clay balls? Is that too ridiculous?

When I said to Murray "How do you plant your veges in these red balls? He showed me. "First wash away all the dirt." Nothing adheres to the plant roots! This is too much I thought. Looks like Hydroponics. Well it is - kind of. Next thing he just plunged the seedling straight into the clay beads. It was a hot summers day and I thought to myself "These plants will be dead by tomorrow."  Yes they did keel over in the hot sun and looked exhausted. Next morning however the plants were standing up straight and looking cheerful. What happend?

Bacteria. Billions of "soil" bacteria were feeding the plant roots the fish poop. They were breaking down the fish waste into minerals. Since we got into Aquaponics we have harvested around 50 Jade Perch around 400 grams. Not big fish but Aquaponics is not about big game hunting. Its about balance. Keeping the right ratio of fish mass to grow bed size. Too many fish and you will struggle to keep the water flow back to the fish clean. Too little fish and the plants wont have enough nutrients.

What about plant nutrients? How sustainable is it? Do fish pellets which are grown from depleted sea reserves of ocean catch the right way to go? Its a valid question and one that we are looking at eliminating eventually. We know Jade Perch will eat green vegetables. The stuff we grow - we feed back to them. They love lettuce. We grow compost worms in a seperate bath tub system and they will devour the worms with glee. You can also grow black soldier fly larvae and the the larvae can be frozen for use over winter. Duckweed is another good source of protein that fish love to eat. We have grown all this and its not hard to do. In the back of my mind the question of how nutritionally dense is the food grown in Aquaponics? Is it deficient in certain minerals not found in fish pellets? Well the vegetables grown look perfect to my untrained eye. We have grown tasteless tomatoes and we have grown sweet full flavoured tomatoes just the way you imagine the perfect tomato to be in aquaponics. It all depend on the variety of the produce you choose. But to be on the safe side - because we don't have all the facts - I like to give our aquaponics system a good slurp of worm juice.Remember it is all about cycling nutrients through the bacteria and back through the worms and back through the plants and back into your body and so on.

There are many mineral elements in worm juice and its also harmless to fish.

Its now our second year with Aquaponics. The system does mature over time and I believe that as a system matures various heirachies of microorganisms colonise the system and enrich the system. We have grown heaps of vegetables. So is Aquaponics the Answer? It wont save the planet. People will still require a high carbohydrate diet in corn or wheat or rice, but for a small urban garden space and we have a small courtyard system - you really can't beat it for the sheer volume of fish and vegetables it will produce continually for many years. Today we took delivery of 50 very small Jade Perch fingerlings that went into the system. The cycle continues...