By Trista di Genova & Chris Simmons
The Wild East
We know it works. Aquaponics is booming in Australia at present because of the water shortage. By contrast, farm-raised fish are raping the sea environment…
Modern aquaponics started about 30 years ago, created by aquarists and their fish aquariums. They were dealing with plants in their aquarium for aesthetics, and someone thought that if water-based plants can grow, maybe also land-based plants can grow in these places.
Aquaponics has been going on for hundred of years; the first example might be in China, when traditionally they would use catfish in rice paddies. It helps fertilize the rice, and they eat insects.
About 30 years ago, people discovered the beauty of aquaponics: it solves two of the world’s biggest problems in two industries, by combining them. In aquaculture, fish farmers have to filter out fecal waste, as well as ammonia as it builds up in the water supply. This wastes a lot of water; 20 percent of it’s dumped regularly to maintain water quality. In deep water aquaculture, one square mile can produce as much waste as an average-sized city; this happens because the fish are force-fed an enormous amount of food, and since they are stationary this creates fecal waste that builds up in a localized area below the farm or can drift with ocean currents and damage the ecosystem in other areas as well.
In hydroponics, the main drawbacks are that plants require nutrients to be added into the water supply which is then provided to the plants. A lot of nutrients have to be purchased, and because plants use various amounts and types of nutrients throughout their life cycle, farmers can’t tell exactly when more are needed without the use of expensive equipment. Even with the equipment, the nutrient-rich water needs to be thrown out regularly, wasting water, nutrients and money. When these nutrients are thrown out, they strain city sewage treatment facilities or get into the groundwater as is true for normal agriculture, and put a huge burden on the environment and infrastructure.
But if you combine aquaculture and hydroponics, aquaponic plants extract the nutrients (waste) that the fish are producing out of the water through the nitrogen cycle that occurs in nature, and use them as plant food on site and can be used immediately to grow profitable, leafy vegetables, which work best. With aquaponics, you don’t have to waste water, or pay for nutrients. In this way, aquaponics is 80 percent more efficient than either aquaculture or hydroponics for water conservation. So the next biggest challenge is finding the right balance between plants and fish.
Different plants need different nutrients and quantities, and different fish live in different Ph levels, so this system is not fool-proof — you can’t grow everything at once. Size and type of the plant, and growth rate of fish must be taken into account. Lots of variables go into it, although everybody seems to have pretty good success with the leafies — lettuce, spinach, bok choi — the solutions take a lot of tweaking. You need knowledge of fishkeeping and hydroponics — and aquaponics.
As for growing fish, tilapia is the most common, and it’s also the world’s most consumed fish. It’s very hardy, and grows from 2 inches long to plate-sized in eight months; plus, they eat almost anything.
Today there are many aquaponics farms in Taiwan, although there are more in the U.S. that are run by the Taiwanese, especially growing orchids, a cash crop, a global industry that’s growing rapidly. The only problem they have is water lost through transpiration, or evaporation.
These same successful principles in aquaponics are not limited to leafy greens such as: lettuce, bok choi, spinach, basil, mint, watercress, but can grow other things as well such as tomatoes, cucumbers, and squash. The most enjoyable aspect is that you can add so many other components for the daily nutrients you need, and for the waste that you produce.
In aquaponics, your largest input will be fish food, but when you are also growing a garden that produces plant matter as waste, the waste products can be composted by the use of vermiculture -– using worms to speed up the decomposition process — and provide food back to the fish. The worms break down plant waste and fish excrement and grow to provide the food for fish helping to offset the fish food cost. Often, black soldier flies are also used, or duckweed as well (which are 30-40% protein), on top of worms to provide a more balanced diet for the fish. Once you calculate how much food the fish need, and how much is provided plant waste, you can calculate your fish food costs.
There are many ways to use your garden — you can grow rabbits, chickens, or most efficiently, Japanese quail for their eggs, which only need a small habitat. Any vegetables which has been attacked by insects or disease can either be fed to the worms, the animals, or the fish. Maybe the system is not fully self-sufficient, but it’s 80 percent so, and will be free of any outside contaminants, such as mercury, which is a problem in Taiwan.
Chris Simmons has been working with Kyle Sveinson and Zach Touzin on implementing several experimental aquaponics gardens in Taiwan.
Trista di Genova has developed a botanical garden on her Rooftop, and is hoping to soon put into place a fully self-sufficient aquaponics system.