| By Adrienne Cohen
Freelance Writer |
Imagine salad greens harvested from your own backyard three to four times a week. Delicious, inviting herbs to season your meats and vegetables. Enough fresh-caught tilapia to feed a family of four at least one meal per week. A teaching aid for your children, showing them how food grows and the interdependence of the food chain. An opportunity to contribute to community health and sustainability. A new dimension to the traditional garden. Does any of this sound appealing?
To an increasing number of North Texas residents, it is more than appealing. For this new breed of urban farmer, aquaponics, or the culture of fish and plants in a single, natural system, is the wave of the future. And for Adam Cohen, who teaches biology and environmental science to high school students, the desire to spread the word about aquaponics is almost a “calling.” He is one of only a handful of Texas residents who is involved in the burgeoning technology, and is in the forefront of regional efforts to explain, promote and deliver aquaponics systems for both individual users and for possible community-wide and commercial ventures. Applications for “backyard” farming are almost limitless, and the implications for community programs and for educational pursuits are exciting and innovative.
Cohen says the birth of his son in the spring of 2008 changed his life. He describes his life then as “pretty typical,” without much thought or concern about the methods of production or costs of the food he ate. And, at that time, he did not eat fish or seafood. He didn’t care about the nutritional content of foods, the processing or the additives in foods. He had never, at that point, grown a tomato or picked a fresh sprig of rosemary. But, as he says, “I held my son for the first time, and I had no way to realize the gravity of the change — my life was never going to be the same again.”
His quest began. His first impression of aquaponics, which he read about originally four or five years previously, was more a passing curiosity than a real interest. He remembered it, he notes, only after reading several books “that orbited around the sustainability movement.” With degrees from Texas A&M University in Marine Biology and Marine Fisheries, he had always been interested in fish. He had experience in traditional aquaculture (fish farming) and was knowledgeable about fish biology, species management and conservation. Almost four years ago now, he notes, he converted his 10-gallon fish tank into a small experimental system. “It was at that point that I fell down the rabbit hole,” he claims.
Since that time, Cohen has amassed an impressive store of knowledge about the variety of aquaponics systems being designed and constructed around the world. The possibility of employing such systems to alleviate worldwide food crises and to supply fresh produce in developing countries and in previously deficient areas is immensely appealing, he notes. He has visited with and learned from proponents throughout the United States and from a number of other countries. He is an avid reader, and is willing to experiment with different systems. To that end, he has constructed several of his own working systems — one in a garage, a large backyard prototype that has a 275 gallon fish tank and almost 60 square feet of grow-space, and a highly-modified installation in his classroom that began as a DIY “barrelponics” system from free plans that are available on the Internet. This last system is maintained by Cohen and his students throughout the year, and it produces thriving crops of greens, tilapia and, one year, even rainbow trout.
The term aquaponics refers to a synthesis of the more traditional aquaculture (culture of aquatic animals) and hydroponics (growing plants without soil). The difference is that in aquaponics, the two halves are joined together in symbiosis. There is no waste and there is no need for synthetic fertilizers or antibiotics — just like any healthy natural ecosystem, everything is balanced and nothing is wasted. The bonus, therefore, is that the fish can become a “crop” in the same way as the plants.
There are many models available for the cultivation of aquatic species and a wide variety of food crops, employing a recirculating system which allows beneficial bacteria to break down toxic ammonia in fish waste to nitrites and then to nitrogen, which is a required nutrient for plant development. Most of the systems are simple to build and well-suited for the do-it-yourselfer, require very little maintenance and are ideal for the casual or part-time operator. It is only feeding the fish and harvesting the plant crops that require any effort.
A multitude of plant crops can be grown in water, from herbs to tomatoes, beans and fast-growing salad greens, to melons and avocados. Even aloe vera and rosemary can be grown in these systems with exceptional results. System size is adjustable, as well, from a small tank and grow-bed installed in a garage with an artificial grow-light, to an outdoor installation with a greenhouse cover and heat for the winter. In Texas, of course, some sort of cover is recommended for outdoor systems, as protection from the effects of sun and heat. And, says Cohen, the fish do not necessarily have to be grown for food. Goldfish or koi, grown for pleasure or for profit, are just as suitable for the backyard gardener. He also notes that he and others are exploring the possibility of “farming” fresh-water shrimp in aquaponic systems.
One of the things that helped Cohen fall in love with aquaponics is the simplicity of it. “As long as you remember a few basic principles,” he says, “these systems will pretty much take care of themselves.” In workshops and when explaining his systems to visitors, Cohen breaks these principles into three main concepts:
- Water flow is important. Move the water from the fish tank to the grow space and then let it drain back. The more movement you have the better it is overall — the water temperature is more even, there is more oxygen in the water through increased aeration and there is more filtration because the water flows through the media more often.
- Follow the general ratio of 1 pound of fish per 4 gallons of water in your fish tank and 2 gallons of grow-space per 1 gallon of fish tank. Remember, there are almost 8 gallons of volume in one cubic foot.
- Do the best you can to keep the pH of your system around 6.5 to 7 — that will maximize the uptake of micronutrients for the plants and also keep the fish healthy and happy. Your system will grow and survive at any pH from 5.5 up to 10, he says, but he has found the “magic” level to be about 6.8.
The systems themselves are designed as gravity-flow systems, with a single pump at the lowest point in a sump tank and the fish swimming in the highest-level tank. The water in the fish tank overflows into the grow beds and then into the sump, from which it is pumped back to the fish reservoir.
The first large system that Cohen built was the one that still operates in his classroom. This system started out as a “barrelponic” system as designed by Travis Hughey and even constructed using the free manual from Hughey’s website (www.fastonline.org). This is a great manual for anyone interested in DIY tinkering and ultimately redesigning. Cohen’s classroom system has been rebuilt and modified many times by him and his students to make it more effective in its location.
“Keep in mind that aquaponic systems can be made out of almost anything — food grade barrels or stock tanks, lumber and pond liner are always good, and there are even systems made from old bathtubs. In designing your personal system, you are only limited by your imagination,” he notes.
In his outdoor system, Cohen has employed two food grade IBCs and five 55-gallon plastic drums cut in half, along with PVC pipes of varying diameter and some lumber and concrete block. It was installed in just a few hours one Saturday through the efforts of a group of untrained volunteers who wanted the experience prior to committing time and resources to install their personal systems. Subsequent adjustments and tweaking of the system were needed to assure the proper drainage and water flow, and to eliminate all leaks; but they were accomplished easily and quickly by novices. It was designed as a demonstration system, much larger than the average backyard gardener would need, in order to allow for experimentation with a variety of crops during a single growing season. Goldfish were introduced initially in the fish tank to stabilize the water, and then Cohen added fingerling Mozambique tilapia, which grow to eating size of between one and one and a half pounds in six months. Pure-bred Mozambique tilapia are the only tilapia species that can be raised in Texas without a state permit (all others and hybrids are highly regulated); and they grow quickly and are an especially good eating fish.
Plant crops are widely varied. Lettuce grown from seed should be harvestable within 45 days, according to Cohen, but does not like the extreme heat of Texas summers. Many herbs thrive, even in the summer. Tomatoes produce extremely well in the spring and the fall. A simple shade cover should assist backyard growers produce crops with relative ease. Cohen’s system produced green beans, snow peas, Swiss chard, cucumbers, eggplant and even cantaloupe. In his school system, Cohen and the students have colorful crops of rainbow (Swiss) chard and oregano, along with more common salad greens. Bok Choy is a favorite, because it is leafy and hardy as well as fast-growing.
Different growing media can be employed in an aquaponic setup. Cohen uses expanded shale for his backyard system, but a more expensive medium, hydroton (or expanded clay) in his school system. Both function equally well as growing media, but hydroton is preferred by some due to the significantly lesser weight.
An aquaponic system can have far-reaching applications and benefits as an adjunct to a community garden, as well as commercial possibilities, and it could be adapted, as Cohen is eager to point out, to supplement a full-scale food-production and distribution system to assist the needy. Aquaponic food production is also in the forefront of many educational programs and should, he notes, be a part of any curriculum focusing on agricultural systems. As he talks and his enthusiasm for the subject becomes evident, it is difficult not to get caught up in the idea.
The model for Cohen’s dream here in North Texas is the Milwaukee, Wisconsin, based Growing Power, Inc., a non-profit organization founded by former pro-basketball-player-turned-farmer Will Allen in 1993. Allen’s “Good Food Revolution” began as a way to put disadvantaged youth to work producing food for their communities, and has grown into a multi-faceted organization which has gained national attention. The organization is making incredible inroads in creating urban farms to produce food, create jobs, deliver food to needy recipients and teach new methods, and to supply farm stands and markets in areas which previously had little access to fresh, locally produced products. Eliminating “food deserts” which exist in many areas across the country and promoting global education and innovation in sustainable food systems are only two of the stated goals of the organization. In 2011, Growing Power, Inc. announced the receipt of more than $1 million in funding support from Wal-Mart to assist with the development of 20 regional outreach training centers across the county. To read more about the exciting work being accomplished, check out www.growingpower.org
Cohen traveled to Milwaukee to attend a workshop in the spring of 2011, toured the facility in Milwaukee and returned to Texas with the goal of replicating those efforts in his area. Aquaponics, in such a model, is only one aspect of a total food production “family,” and that is what this local teacher envisions in the Dallas/Fort Worth metroplex. He has consolidated his efforts to spread the word about aquaponics. He established and maintains a website (www.GreenPhoenixFarms.com) on which he posts articles of interest and through which he gives advice and offers assistance to anyone interested in the subject.
Last year he took a further step by establishing the DFW Aquaponics Meetup group, which has an increasing number of regular participants. The group also schedules periodic workshops on aquaponics systems as well as on additional topics, such as building a strawberry tower and (this past January) a session on seed starting. Cohen welcomes suggestions for future discussion topics. He has made presentations to Dallas area public schools, community organizations, various North Texas municipal departments and several commercial enterprises on the viability and profitability of aquaponics systems. He stresses the benefits to be reaped by establishing aquaponics systems in conjunction with community farms, educational institutions and local food-sales and food-service operations. He notes that he would love to find restaurant chefs willing to buy and cook with locally produced and delivered fresh salad greens and herbs. He says he feels compelled to pass along the knowledge that he has to anyone “who has even the stirrings of a desire to learn it.”
It’s about sustainability. It’s about good food. It’s about self-sufficiency. It’s also about providing a vehicle to demonstrate the interrelatedness of the food-growing lifecycle. Cohen’s vision for the near future includes a tract of land which would include indoor and outdoor growing beds, a composting facility, perhaps a worm farm and a mushroom “cellar,” possibly laying hens — all this to show that it is possible to produce and distribute good food locally. He incorporates seminar rooms into that vision because he is a teacher, after all, and he would like to disseminate what he has learned. “Food production is something that any person can do if he has the desire, inclination and the training. There is no magic to it. There is no special location, or seed, or soul,” he says, “It is simply that many people today have never visited a farm, much less ever tried to grow any type of edible plant.”
Cohen has grown in knowledge and commitment over the past several years. He always liked to cook; but now preparing meals is a labor of love and a journey of discovery, utilizing fresh ingredients and locally grown produce. He is adamant that his family becomes aware of the difference between high-quality, good-tasting, locally produced food and the alternative of mass produced, genetically altered, additive-filled, unhealthy offerings. His infant son has grown, as well. The almost four-year-old now enjoys helping his dad feed his fish and loves to pick vegetables, fruits and herbs from the grow beds. He eats the “leaves” on his plate and is learning about nutrition and food in the best possible way — from personal experience. He, like his dad, enjoys “getting his hands dirty” in the growing medium. He, like his dad, knows about the fish. Oh, and his dad now eats fish, too!
