OK, I’ve taken the plunge and embarked on my Home Aquaponics project. In Newtopia – Aquaponics 101 I introduced the concept of Aquaponics, ie the integrated grow-out of fish and vegetables in a balanced and sustainable system.
The beauty of aquaponics is that it can be tiny. There are some system that merely consist of a couple of goldfish and a potplant !! However small, the basic principles apply. Here is an image of a tiny system from Backyard Aquaponics
Then there are full-scale commercial facilities. Here is a picture of a Basil and Tilapia system in the Virgin Islands.
My system is going to be somewhere in between. Here are the rough specifications.
Land area : 8m x 7m
Greenhouse : PVC tube frame, clear plastic cover for fish tanks 3.5m x 5m.
Fish Ponds : 3 ponds 1.2m deep and 1.75m diameter. (1 communal, 1 for babies, 1 male grow-out)
Grow Beds : Under shade-cloth, outside the greenhouse in 5m gravel-filled troughs, flood and drain irrigation directly from fish ponds.
Fish : Tilapia (Oreochromis mossambicus)
Plants : Lettuce, spinach and any other leafy vegetables.
Some explanations of my decisions;
- The land area is determined by the space I can spare. Although I have a large garden, it is steeply sloped and this is about the biggest I can make a terrace.
- I have looked at various greenhouse options and also just using shade cloth. Although it will work in summer, the winter temperatures will be too low for the Tilapia. I need a constant temperature (water/air) of 24-28 deg C for the fish to be happy. I have eventually decided to design and build my own greenhouse out of 40mm PVC piping (similar to plumbing pipes) . Over this I will stretch proper greenhouse plastic.
- I am using small Hydrex mesh ponds. The reason I have gone for shallow (1.2m) ponds is in case I have problems with dissolved oxygen levels. Smaller ponds are easier to aerate. By having three ponds I can separate my fry (Tilapia breed like crazy) from my communal tank. My third pond is for some special all-male Tilapias that I am hoping to try out. Apparently they grow at a much faster rate than mixed fish.
- I am still looking for suitable furrows to use as grow beds but have decided on 8mm granite gravel as my grow media.
- The Mozambique Tilapia is legal in South Africa and is a great hardy fish for Aquaponics. With catches of wild fish drying up, farmed Tilapia is set to boom in this country. Ocean Basket already have it on their menu.
- As you can see I am going to try leafy vegetables. Apparently they are easier for beginners.
- The reason that I am housing my fish and vegetables separately is because of the different temperature requirements.
Here is an image of my “early-beginnings” I will report back weekly.