Posted by Nigel
Here’s the reason there’s been very little recent activity on the blog – we’ve been working hard on our new side project – our Headford backyard aquaponics system ….
Put simply, aquaponics is the integration of hydroponics and aquaculture, a recirculating method of sustainable food production. The process basically entails pumping nutrient rich effluent from fish tanks which fertilizes hydroponic plant beds, and, in turn, the plants function as a biofilter, removing the ammonia, nitrates, nitrates and phosphates from the water. The cleaned water then recirculates back into the fish tanks.
An aquaponics system is made up of two basic elements – a pond/tank for your fish and water reservoir and a grow bed for the plants.
This summer we’re experimenting with a small ‘backyard’ system, comprising three ponds and three grow beds. Following the photo’s above clockwise from top-left will give an idea of the amount of work involved in just preparing this small system. In the first photo, we’ve cut the top off an IBC (an intermediate bulk carrier – a plastic industrial container) to give us our basic tank and grow bed. We’ve tried to scavenge what we can in order to minimise costs but this was our greatest expense (€200.00 for the three). The next step is insulation to cope with temperature fluctuation. The second photo shows an aborted attempt using Polyurethane foam (yes, we should have tried putting it on before filling the tank with water!), and the next shows the finished tank and grow bed. In the end we used fibre insulation wrapped in black plastic sheeting kept in place with pallet wrap. Our grow beds are gravel filled (and cleaning the gravel proved to be the most intensive element of the set-up work), with simple wavin pipe irrigation systems. Our pumps are the cheapest pond pumps we could find online – about €65 each. In total we estimate we’ve spent about €800 between everything at this stage (add water testing gear, electrical fittings and sundry bits and pieces). We also bought some goldfish to get the whole ecosystem going.
The working model is also depicted above with water flowing from the plant bed drain and the pump in the, as yet, unpopulated fish tank. As you can see we have planted a few plants in one of the grow beds (lettuce and basil) and all is well so far.
We’ll be introducing our main fish stock shortly and we’ll go into more detail over the next few months, and keep readers abreast of progress. Hopefully we’ll be reporting a thriving little facility and be eating lots of trout, perch, lettuce and basil all summer (well – we won’t have fully grown fish that soon). There’s a thriving aquaponics community worldwide and it’s a very exciting field. If nothing else it should be good, clean summer fun. Most of the information we’ve garnered is from Joel Malcolm’s excellent book and forum available at Backyard Aquaponics.