Unfortunately, for those of you who aren’t up to date on your agricultural terminology, the explanation of aquaponics requires the use of various long and somewhat technical terms. In brief, aquaponics is a system that combines hydroponics and aquaculture. The former is a nutrient rich water based planting system that doesn’t require soil, the latter is the farming of aquatic animals in controlled conditions, usually in tanks. Together, these two forms of farming – plants and fish – enjoy a symbiotic relationship in the form of ‘aquaponics’.
In Kate Humble's crude terms, ‘you’ve got your fish in your tanks, tilapia – which do well in aquaculture - shitting away merrily, and that water full of nitrates is pumped through vegetable beds. The leafy greens love the nitrates and grow like fury, the vegetables clean the water and back it goes to the fish.”
So, let’s see this in a bit more detail. In aquaponics, the excrement from fish, which would otherwise accumulate and create toxicity in an aquaculture, is used in a hydroponic system to provide nutrients for plants. Nitrifying bacteria that exist in the growing medium convert the ammonia from the fish waste into nitrites and then nitrates. Subsequently, the plants take up the nitrates and grow, in doing so filtering the water for the fish to live in. In the best and most sustainable aquaponic systems, the cuttings from the plants are also collected and composted, thus providing food for worms to grow, multiply and subsequently be fed to the fish.
The benefits are numerous. Aquaponics creates a self-sustaining cycle that can produce a variety of different foods in small spaces all year round (i.e. both fish and different types of greens can be grown, rather than simply a monocrop). The system is a closed-loop, which prevents a lot of waste; an estimated 80 to 90 percent less water is required here than in traditional growing methods.
The next question begs - what are the yields? According to Charlie Price, the founder of Aquaponics UK, 1 kilogram of fish food will produce at least 50 kilograms of vegetables and 0.8 grams of fish.
So, now we’ve got the facts out of the way, let’s have a look at the amazing things people are doing with this technology. Arora and Velez, the same guys that created ‘Back to the Roots’, a grow your own mushroom kit for the home, have created a DIY Aquaponics kit called the Aquafarm. This neat thing can sit on the top of your desk or kitchen counter for the grand total of 60 dollars and it comes with everything that's required except for the fish, which you get a coupon for from the companies partner PETCO. Thereafter you can begin to grow your own basil, wheatgrass and lettuce from the seeds provided, simple as that.
Of course, perhaps more importantly in the grand scheme of things, there are also people trying to introduce Aquaponics on a larger, more commercial scale. A company called Urban Organic’s has set up an aquaponic farm in an old abandoned brewery in Minnesota and is currently raising 3,200 fish!
Aquaponic Gardenind: A Step-By-Step Guide to Raising Vegetables and Fish by Sylvia Bernstein