Aquaponics Printable Version 1.0 by Natasha Johnson

What Will You Grow?

Aquaponics Introductory Guide

By Natasha Johnson Green Mountain College Spring 2012

Image Credits

This booklet is meant to be freely distributed in order to share the knowledge and use of aquaponics. Please feel free to email the pdf or print out the booklet as a whole and pass it around.

inner-city-urban-farming-video.html http://theurbanfarmingguys.com/ http://theurbanfarmingguys.com/ http://crispgreen.com/2011/07/science-barge-demonstrates-urban-farming-onopen-water/ http://www.groundworkhv.org/programs/environmental-education/sciencebarge/faqs/ http://www.good.is/post/making-urban-farming-scalable-with-fish?utm_ source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+good%2Flbv p+%28GOOD+Main+RSS+Feed%29 http://urbanee.wordpress.com/tag/river/ http://blogs.ei.columbia.edu/2011/05/14/the-science-barge-demonstratessustainable-urban-farming/ http://www.seismologik.com/journal/2011/8/7/science-barge-open-farming-onthe-water.html http://www.plantchicago.com/ http://www.fastcoexist.com/1679765/a-meatpacking-plant-transformed-into-avertical-farm http://www.utne.com/Wild-Green/Chicago-Brewery-Goes-for-Zero-Waste.aspx http://article.wn.com/view/2012/04/27/Market_Watch_In_Mar_Vista_an_ aquaponics_farm_just_down_the_s/

Happy Growing

All hand drawings and sketches in this booklet have been composed by Natasha Johnson, if used please give credit. I can be reached at thestraybead@gmail.com

Image Credits In order of appearance excluding hand drawings and sketches: http://www.chinesepaintings.com/chinese-fish-paintings.html http://tolnai-history7.wikispaces.com/7B-+AAA+-+Awesome+Aztec+Agriculture+ %28Peter,+Jake%29+ http://www.cropking.com/NFT_Lettuce_Herbs.shtml http://www.proaqua.com/aquaponics https://locavoredelmundo.wordpress.com/2011/01/29/aquaponicos-de-elsalvador/ http://farmingwithfish.com/ http://knowledge.allianz.com/health/science/?505/killer-genes-battle-pests-andweeds-gmos http://www.houseofannie.com/wild-boar-farms-tomatoes-suisun/ http://www.simplyrecipes.com/recipes/heirloom_tomato_basil_mozzarella_ salad/ http://www.kitchengardenfoundation.org.au/learn-more/resource-area/imagegallery/46/kitchen-garden-schools-at-mfwf http://www.wholesalefishingworms.com/shop/red-worms/ http://sustainablog.org/2011/08/composting-food-scraps-black-soldier-fly-larvae/ http://theaquaponicsource.com/2010/06/07/aquaponics-and-black-soldier-flylarva/ http://aquaponic-gardening.blogspot.com/2011/04/aquaponic-gardeningduckweed-dilemma.html http://gardenpool.org/gardening-tips/growing-duckweed http://www.packagingconnections.com/p-exchange/ibcs-securing-during-transit. htm http://www.tensiletesting-machine.com/products.htm http://www.homedepot.com/buy/outdoors/garden-center/earth-solutions/littletokyo-aquaponics-container-gardening-without-a-tank-81037.html http://www.generalhydroponics.com/blog/2009/02/18/what-does-it-dowednesday-expanded-clay-pebbles/ http://www.yixinky.com/english/qitachanpin.html http://www.traditionaloven.com/articles/312/vermiculite-insulation-what-isvermiculite http://efundies.com/projects/2_liter_bottle_hydroponics/ http://www.sharecost.ca/img/bulk/bedding_sand_lg.jpg http://ocr.org/portfolio/perch/ http://www.tnaqua.org/newsroom/trout_pr.asp http://www.kidkoi.com/wp-content/uploads/2010/07/Buying-Koi-fish-1024x768. jpg http://gallery.nanfa.org/v/members/Uland/Family+Cyprinidae/Semotilus/Semotil us+atromaculatus+Creek+Chub+1268.JPG.html?g2_imageViewsIndex=2 http://wakeup-world.com/tag/the-good-news/ http://www.lavidalocavore.org/showDiary.do?diaryId=2570 http://www.theslowcook.com/2009/11/12/growing-power/ http://dbpedia.org/page/Aquaponics http://urbanfarmstourkc.com/?page_id=564 http://www.treehugger.com/green-food/20-families-uprooted-from-suburbia-for50

Table of Contents 4 6 8 10 12 14 16 18 19 20 20 22 23 24 26 28 30 32 34 38 42 46 48 50

Introduction of the project Aquaculture Hydroponics Aquaponics The Arguement for Aquaponics The System Closing the Loop The Containers Growing Media The Nitrogen Cycle The Essential Elements The Yellow Perch Other Fish Growing Power The Urban Farming Guys The Science Barge The Plant Construction Foreword Tilt Babylon IBC Works Cited Resources Image Credits

Resources

Introduction of the project This booklet will provide the reader with a basic grounding in aquaponics for those who want to try a system of their own or who just want to get to know the subject better. It covers the basic systems, requirements, input and outputs, as well as gives profiles of larger scale operations. There are three designs included with instructions, materials list and plans. There are further resources at the end of the booklet for those who want to dive more deeply into aquaponics. Aquaponics is a food system that has been on the fringes on agriculture for a while. It has been put to use in large growing operations in a few instances, remaining largely a hobby activity for those who want to grow intensively or in circumstances that are unfriendly to traditional agricultural needs. Aquaponics is the pairing of two growing systems, aquaculture and hydroponics, to create a method of growing that uses less water than traditional farming, recycles the water it does use, and makes use of the waste created by the fish. This last aspect is of much importance in aquaponics, as it is used as the feedstock for the plants which, in turn, clean the water before it is returned to the fish. Nitrogen in this cycle is particularly important and the ammonia created by the fish waste is chemically changed twice by bacteria that use it as food. The end result is then able to be taken up by plants The physical system can be broken into three parts: the fish tanks, the filter and the growing beds. Each can be made of what materials one has on hand. The system, instead of a set physical design, is a collection of needs that can be met in many diﬀerent ways and on many diﬀerent scales. I have provided three designs of my own that can be employed by someone who wants to try out a small system that doesn’t require a great deal of time or attention. The first two systems provide herbs and greens from typically sized aquariums that have been stocked with non-edible hobby fish. These systems can be placed on already existing aquariums and provide both filtration and edible plants. The last system is for growing both edible plants and fish using a container that is common and relatively inexpensive. The larger system can also be stocked with non-edible fish if the grower doesn’t want to farm fish. This booklet will assist the reader in understanding the process of aquaponics, its strengths and weaknesses, and how they can try out a system of their own through the use of the plans included. I am excited to share what I have learned and I hope that it helps you to appreciate the potential of q p aquaponics.

Community Food Centers, as a key component of Community Food Systems, through training, active demonstration, outreach, and technical assistance. http://www.growingpower.org/index.htm The Plant is a new kind of organization in a very old building. It’s part vertical farm, part food-business incubator, part research and education space – and it will be entirely oﬀ the grid. http://www.plantchicago.com/ The Science Barge greenhouse, floating on the Hudson River, grows an abundance of fresh produce including tomatoes, melons, greens, and lettuce with zero net carbon emissions, zero pesticides, and zero runoﬀ. http://www.groundworkhv.org/programs/environmental-education/sciencebarge/ Instructions of how to make a hanging gutter garden. A good reference for the Babylon design. http://nestinstyle.com/garden/how-to-make-a-hanging-gutter-garden/ This is an in depth guide of how to build aquaponic systems using plastic barrels. It is good for residential application. http://www.aces.edu/dept/fisheries/education/documents/barrel-ponics.pdf This is an extremely in depth guide of IBC aquaponic systems. It has an introduction of aquaponics and multiple iterations of a variety of IBC systems. It is a large document and a valuable resource. http://backyardaquaponics.com/Travis/IBCofAquaponics1.pdf These two sites explain how to construct bell siphons. Bell siphons are used mostly in flood and drain systems. They automatically drain water after it reaches a certain level. http://www.ctahr.hawaii.edu/oc/freepubs/pdf/BIO-10.pdf http://www.japan-aquaponics.com/bell-siphon.html

Resources How I fell in Love with a Fish is a wonderful look at an alternative viewpoint to what farming can be. http://www.ted.com/talks/dan_barber_how_i_fell_in_love_with_a_fish.html This is an article by the Los Angeles Times that links the taste of tomatoes with their appearance. The gene that gives store bought tomatoes their uniform color makes them less sweet. http://www.latimes.com/news/science/la-sci-tomato-taste-20120630,0,4449608. story More on the nitrogen cycle. http://www.gardencentredirect.co.uk/Article/the-nitrogen-cycle-explained A good vermiculture resource that is knowledgeable about raising worms in northern climates. http://www.vermiculturenorthwest.com/worms.htm This article gives information on raising trout in New Mexico Ponds. It provides recommendations for the climate, size and other variables. http://aces.nmsu.edu/pubs/_l/L-108.pdf A brief summary of the attributes and benefits of the Yellow Perch by Fisheries Technology Associates in Colorado. http://www.ftai.com/articles/GAAManciDec00.pdf A more in depth look at the life cycle of the Yellow Perch by Maryland Department of Natural Resources. http://www.dnr.state.md.us/irc/docs/00000260_14.pdf Murray Hallam is an Australia authority on aquaponics. He had experience with many diﬀerent systems and warm weather growing. http://www.aquaponics.net.au/ The Urban Farming Guys- Food hitting our plates with who knows what pumped into it and growing economic uncertainty. We took the seeds in our pockets and every square foot we owned and went about like mad scientists testing out innovative ideas from all around world and making them work in one of the most blighted neighborhoods in the US. Everything from urban fish farming to alternate energy. Now let’s pass it on... to our neighborhoods and the nations. We believe you are part of the solution. http://theurbanfarmingguys.com/ Growing Power transforms communities by supporting people from diverse backgrounds and the environments in which they live through the development of Community Food Systems. These systems provide high-quality, safe, healthy, aﬀordable food for all residents in the community. Growing Power develops

Aquaculture

Works Cited

The Food and Agriculture Organization of the United Nations defines aquaculture as “the farming of aquatic organisms: fish, molluscs, crustaceans, aquatic plants, crocodiles, alligators, turtles, and amphibians. Farming implies some form of intervention in the rearing process to enhance production, such as regular stocking, feeding, protection from predators, etc.”. Aquaculture’s exact origins is unknown, but records in China date back to around 2000 B.C. Slightly later in the 5th century B.C., the first written guide to aquaculture was written by Fan Lee, a politician and fish enthusiast. “The Chinese Fish Culture Classic” gave instructions of how to raise carp, a noncanablitic and cheap fish to raise. Chinese fish culture continued to grow and prosper, expanding into the stocking of diﬀerent breeds in the same pond, fry collection from wild stock, transportation of fry, pond structure, disease, fertilizers and rotation. Also early on in the Western world, aquaculture started appearing in various forms, including brackish water farming and the spread of fish to artificial bodies of water at monasteries, palaces, etc. In North America, aquaculture was mainly of interest because it could be used to stock game waters. Some countries in Africa started to culture carp, tilapia and catfish. Today aquaculture has experienced a flourishing because of widespread communication, exchange of information and technologies that allow close monitoring of ideal conditions.

“Overfishing: A Threat to Marine Biodiversity.” UN News Center. UN, n.d. Web. 05 June 2012. <http://www.un.org/events/tenstories/06/story. asp?storyID=800>. Piavis, Paul G. Yellow Perch: Perca Flavescens. Maryland Department of Natural Resources, Fisheries Division. Web. 2 Feb. 2012. Pollan, Michael. “Cruising on the Ark of Taste.” Mother Jones May-June 2003: n. pag. Web. 30 Mar. 2012. <http://www.professorlonniegamble.com/ uploads/ArtisanFoodSlowFood/ArkOfTAste.pdf>. Richard, Tyson V., Eric H. Simonne, James M. White, and Elizabeth M. Lamb. Reconciling Water Quality Parameters Impacting Nitrification in Aquaponics: The PH Levels. Florida State Horticultural Society, 2004. Web. 2 Mar. 2012. <http://www.fshs.org/Proceedings/Password%20 Protected/2004%20v.%20117/079-083.pdf>. Salatin, Joel. The Sheer Ecstasy of Being a Lunatic Farmer. Swoope, VA: Polyface, 2010. Print. Van, Der Ryn, Sim., and Stuart Cowan. Ecological Design. Washington, DC: Island, 2007. Print. Ver Ploeg, Michele, and Vince Breneman. “USDA ERS - Food Desert Locator.” USDA, n.d. Web. 08 June 2012. <http://www.ers.usda.gov/data-products/ food-desert-locator/about-the-locator.aspx>. Walker, Polly, Leo Horrigan, and Robert S. Lawrence. “Environmental Health Perspectives: How Sustainable Agriculture Can Address the Environmental and Human Health Harms of Industrial Agriculture.” Environmental Health Perspectives: Monthly Journal of Peer-Reviewed Research and News on the Impact of the Environment on Human Health. John Hopkins Bloomberg School of Public Health, 20 Mar. 2002. Web. 27 Oct. 2011. <http://ehp03.niehs.nih.gov/article/fetchArticle.action? articleURI=info:doi/10.1289/ehp.02110445>.

World Fisheries 2008: Inland Harvest (million tonnes)

Works Cited Boren, Jon, Terrell T. Baker, David E. Cowley, and Brian J. Hurd. Growing Trout in New Mexico Ponds. Las Cruces: Cooperative Extension Service, College of Agriculture and Home Economics, New Mexico State University, Mar. 2003. PDF. Carpenter, Novella. Farm City: the Education of an Urban Farmer. New York: Penguin, 2009. Print. Chevat, Richie, and Michael Pollan. The Omnivore’s Dilemma: the Secrets behind What You Eat. New York: Dial, 2009. Print. Diver, Steve. Aquaponics—Integration of Hydroponics with Aquaculture. ATTRA. ATTRA, 2006. Web. 24 Feb. 2012. <www.attra.ncat.org>. Fowler, Cary, and P. R. Mooney. Shattering: Food, Politics, and the Loss of Genetic Diversity. Tucson: University of Arizona, 1990. Print. Fan, Lee, and Ted S. Y. Moo. The Chinese Fish Culture Classic. Solomons: University of Maryland, n.d. Print. FAO. © 2002-2012. CWP Handbook of Fishery Statistical Standards. Section J: AQUACULTURE. CWP Data Collection. In: FAO Fisheries and Aquaculture Department [online]. Rome. Updated 10 January 2002. [Cited 30 June 2012]. http://www.fao.org/fishery/cwp/handbook/J/en Hayes, Shannon. Radical Homemakers: Reclaiming Domesticity from a Consumer Culture. Richmondville, NY: Left to Write, 2010. Print. Hillyer, Chelsey D. “Is Aquaponics the Agriculture of the Future?” Countryside and Small Stock Journal 92.2 (2008): 83-85. Print. Hinshaw, J. M. Species Profile: Yellow Perch, Perca Flavescens. Southern Regional Aquaculture Center, July 2006. Web. 06 Feb. 2012. <https://srac. tamu.edu/index.cfm/event/getFactSheet/whichfactsheet/188/>. Horrigan L, Lawrence RS, Walker P 2002. How Sustainable Agriculture Can Address the Environmental and Human Health Harms of Industrial Agriculture. Environ Health Perspect 110:445-456. http://dx.doi. org/10.1289/ehp.02110445 Hughey, Travis W. Barrel-Ponics. 2005. PDF. Jones, Scott. “Evolution of Aquaponics.” Aquaponics Journal 6.1 (2002): 14-17. Print. Jones, Thomas. Approved Sources for Brook, Brown and Rainbow Trout. Vermont Fish and Wildlife Department, 14 Apr. 2010. PDF. Lennard, Wilson A. “Aquaponics Research at RMIT University, Melbourne Australia.” Aquaponics Journal 35 (2004): 18-24. Print. Manci, Bill. “Prospects for Yellow Perch in Aquaculture.” The Advocate Dec. 2000: 62-63. Web. 2 Feb. 2012. Miller, Sean. Classroom Aquaponics: Exploring Nitrogen Cycling in a Closed System Teacher’s Guide. Cornell University. Web. 21 Mar. 2012. “Modern Agriculture.” College of Natural Resources - UC Berkeley. 30 July 2000. Web. 27 Oct. 2011. <http://nature.berkeley.edu/~agroeco3/modern_ agriculture.html>. Nabhan, Gary Paul. Where Our Food Comes From: Retracing Nikolay Vavilov’s Quest to End Famine. Washington, DC: Island/Shearwater, 2009. Print.

The United Nations reports that “in the last decade, in the north 10.2 Atlantic region, commercial fish populations of cod, hake, haddock and flounder have fallen by as much as 95%” (1). The state of our Aquaculture ocean fisheries is unsustainable and aquaculture is expected to help solve Capture this growing problem. While fish farming redusces the stress on native populations of fish it 32.9 isn’t without it’s problems. Sourcing food for the farmed fish can also be Food and Agriculture Organization of the United Nations a point of contention; irresponsible practices can be carried through to make the entire process unsustainable, more so if the species is carnivorous and requires more protein than it produces. There is a high parasite population on the tightly spaced farmed fish, and escapees can infect native populations. Escapees can also pollute the genetics of wild populations, instead of passing on traits that are beneficial for the wild; they pass on the genes that the farmer’s favored, making the population weaker as a whole while competing for food and spawning grounds. In systems that have a high population in close quarters, disease is always a danger. Salmon farmers fear infectious salmon anemia and often the only way to deal with an outbreak is to cull all farmed fish in the surrounding area. Wild fish could still act as vectors for the disease. Fish can carry the unprocessed remnants of antibiotics in their flesh, which can be consumed by humans and have negative impacts. Large scale operations can release a great deal of waste into the environment if the farm is in open water. This waste can cause eutrophication, severlying impacting the health of the ecosystem. The extra nutrients that are released by the fish are consumed by algae, which take in CO2 and release oxygen. The algae swiftly mutilply, causing an algae bloom. The bacteria that normally feed on the algae likewise increase in number, feeding on the glut of algae. The bateria require oxygen to consume the algae, which isn’t a problem in the day, when the algae are producing oxygen. But by night, the algae stop World Fisheries 2008: Marine Harvest (million tonnes) growing and reproducing, so the water can become starved of oxygen, 19.7 killing oﬀ both macro and micro life. Aquaculture shouldn’t be considered something horrible, to be discarded. The protein it provides Aquaculture is important to the worldwide food supply. More importantly, Capture aquaculture can be done right. Dan Barber’s TED talk, “How I Fell in Love with a Fish” is a wonderful example of what a fish farm can be. 79.5

Food and Agriculture Organization of the United Nations

Hydroponics

This system has a bell siphon which regularily release the water directly back into the tank. Many systems have a sump tank where all the water flows before it is pumped back into the fish tank.

Historically, growing plants in water isn’t uncommon. The Aztec had to grow crops on their marshy land, so they developed a solution: a floating island. These “chinampas” are preserved and still used today, retaining their cultural value while still functioning as a working farm. Today, hydroponics promises the potential of growing plants in places that are typically unsuited to agriculture because it needs less water than traditional agriculture and can be place almost anywhere. Hydroponics can be deployed anywhere they can fit, even inside or underground with grow lights replacing the sun. Supplying the nutrients can be energy intensive because they have to be mined or harvested, then transported to the growing site. Systems can be very expensive as well, if large and digitally controlled. If the operation is outside, the plants need to be protected from the elements, normally with high tunnels, a form of greenhouse. The cost of the infrastructure can make the system out of reach for many small operations. The ease of growing hydroponically is alluring. There is essentially no weeding because of the lack of exposure to weeds; there is no bank of weed seeds waiting to sprout, unlike in soil. If a weed does find purcahse in the system it takes only moments to remove it. Plants are grown oﬀ the ground, making them easier to monitor, care for, prune and harvest. Many pests that depend on soil cannot survive the conditions of hydroponic growing or access them because of the physical barrier.

Cut through view from the right The compact design allows the fish to be sheltered from direct sunlight and hides human activity. A cover could easily be placed over the from of the open tank, further reducing stress on the fish.

Hydroponics Hydroponics is growing plants without soil. Instead a growing media is used for structural support and nutrient rich water to plants in growing media. The solution is carefully controlled and monitored, often by computers. Hydroponics in its modern incarnation is relatively new. There are several diďŹ&#x20AC;erent types of systems:

The filter buckets rest on the build in shelf in the back of the bench. Water is taken from the tank and pumped into the far left bucket pumped into the growbed from the far right bucket.

Flood and Drain- a very common type for small scale installations. Water constantly fills the grow bed to just below the top of the growing medium. It is then completely drained, commonly through a bell siphon.

Drip feed allows incredibly precise control of nutrients and water. This is often used for tomato growing.

View from the back

Raft System- Also called Deepwater Culture. This system has plants supported by rafts that float on a large quantities of water. This is a very stable system because of the large resevoir. This system is commonly used to grow greens.

Aeroponics uses the least amount of water of all of the systems. Nutrient laden water is sprayed up into the plants roots.

View from the left side

Wick systems are uncommon. They draw water up through a wic into the growing medium. The growing medium has to be able to wick up water.

The nutrient film technique or NFT has the nutrient fluid running down the inside of the growing bed. The roots hang down into the fluid, taking the nutrients as needed.

Aquaponics Aquaponics is the combination of aquaculture and hydroponics. This results in a system with few of the weaknesses of either. The fish are fed, sometimes with byproducts of the system, and their waste goes into some kind of filter. Depending on the size of the system the filter might be a separate entity if the system is large, or might use the growing media as the filter if the system is smaller. The filter captures large particulate as well as acting as the home for helpful bacteria. The bacteria feed on the ammonia from the fish waste and uneaten food, converting it into nitrogen that can be used by the plants. The plants filter out the nitrates, as well as the other nutrients in the water, cleaning it. The water is then returned to the fish. Water use in this system is greatly reduced because there is no extra water needed to compensate for loss to the soil. Like in hydroponics, there is little to worry about from weeds and the pest pressure is reduced. There is no need for herbicides and pesticides, which would negatively aﬀect the fish anyways. Systems are also normally set up for easy care and harvest, so growing food in this way requires little physical labor. Aquaponic systems are normally fairly simple, running by themselves oﬀ a pump and a timer. Monitoring the system isn’t time intensive or expensive, just occasional water tests to ensure that the pH and nitrogen levels are within acceptable levels. Aquaponics today is mostly viewed as a hobby, though there are universities doing research on the practice. There are a few larger groups and businesses that use aquaponics on a large scale, but they are rare when compared to the number of traditional farmers. There are many resources online for the hobby aquaponic fan. The potential use for aquaponics is very high in urban situations. Space in cities is very limited and where there is soil, it can be unsuitable for growing. Aquaponics can be installed just about anywhere because it doesn’t need soil to function. Rooftops can be used without any of the work that would be needed to install a rooftop garden or green roof.

The last system, IBC aquaponics, it an example of a basic intermediate bulk container system. This can regarded as one of the building blocks of residential scale aquaponics. The container holds about three hundred gallons and isn’t well suited for indoor situations. It could be placed in a basement or garage with grow lamps, or the water could be pumped outside to growbeds. The fish tank in this system is more stable in both temperature and nutrient levels because of the larger volume of water. Water is good thermal mass, it hold and keeps heat well. Because there is more of it, the water is able to hold higer level of nutrients and it takes longer for changes to occur. This makes the large system less finicky than the two previous systems. IBC systems are for serious enthusiasts who have some experience with fish and aquaponics. It could also be taken on by a beginner, though they should have access to someone more experienced and happy to give advice. This design, like the others, haven’t been built before and should be regarded as an illustration of how larger systems work and what their components are. In the resources system there are links for complete IBC system plans. The IBC starts as a vessel for food grade material. This is important, if it isn’t food grade it could have been used for chemicals or other potentially harmful liquids. The IBC is normally inside of lightweight metal cage to allow extra support and stacking. Some designs use the frame to support the grow bed. In the case of this design, it unfortunately came without a cage. A wooden bench can be used instead. Cut the top of the IBC off at the depth desired for the growbed. Lettuce needs less and carrots need more, it depends on what will be grown and if it will ever change. At least 12” is a good place to begin. The design of the bench calls for 2x6 legs with a thick plywood top and a 2x6 shelf for the filter buckets. Up to three filter buckets can be used in the system, though it shouldn’t need all three. A settling tank is a good choice here because the larger the growing bed the more difficult it can be to muck out. The settled effluent can be used in the garden and treated like worm tea. The Urban Farming Guys use their effluent to make bio gas, another possiblity for this system. The settling tank can be made out of a ten gallon bucket. There is room for three of the buckets under the bench with any combination of filters. The water is drawn from one filter to the next and then pumped up into the growbed. The growbed can be emptied with a bell siphon if it is a flood and drain system. It kept at a constant level for a raft system with a simple overflow pipe. It could also become a wick system, but further research would be needed. If IBC’s are going to be used in your system, check out the IBC’s of Aquaponics link in the resources page. Materials: cut 2X6 Plywood IBC tote screws pvc pipe buckets pump

IBC

The Arguement for Aquaponics Growing food might seem like a very drastic action to take when there seems to be so much choice available today. The reason to consider trying aquaponics is many-fold. The kinds of vegetables that are in the grocery store right now aren’t there because they taste good, they are there because they look nice and keep for a long time. Most food has to be shipped many miles, sometimes thousands, before it reaches its consumer. In order to ensure that it keeps that long and still looks nice, plant breeders have chosen different characteristics of plants to enhance compared to what our farming ancestors did. Heirloom tomatoes are notoriously tasty and fragile. Often times taking them to the farmers market is a gamble. So quite often people literally don’t know what they are missing. (Pollan) Another persuasive reason is that the home growers know exactly what they are putting into your system. They have watched their fish grow from fry or fingerlings. There are no petrochemical fertilizers needed, nor wanted. Pesticides, if rarely needed, can be organic. Insects picked off plants can be dropped into the fish tank where they will be eaten, or decompose to feed the plants. The grower has watched and waited for that beautiful head of lettuce to become mature enough to pull, for the fish to grow to harvest weight. Food becomes more valuable when it comes from your own labor. Plants grown in aquaponics systems are typically healthier because they don’t have to compete for access to the water and nutrients they need. Many issues that are problematic in typical farming aren’t present here. Home growers can grow vegetables and herbs varieties that they can get nowhere else or if it is available, at a high price. This individualization of food, a regional diversity, can create unique taste and flavor combination that becomes a calling card of the place where the food is grown. Unless you are very good friends with a farmer and a fisherman who bring you food on demand, this is the freshest food that anyone can get. Growing a favorite crop becomes so much more interesting when one realizes that there are normally hundreds if not thousands of varieties of one type of plant. The different varieties arose as humans selected for favored traits. The traits can be general, like a tomato plant with large fruit, or as specific as a distinct sweet and tart taste. Disease resistance is a common reason why there is such variety. Some tomatoes don’t develop a certain kind of mold found in an area, while others catch it every time. Aquaponics can be used as a teaching tool for both adults and children. It is a relatively simple system which teaches about the roles of nutrients needed for growing plants, the importance of unseen life, as well as showing that what is typically considered as waste has an important role to play. It can be used at the center of food deserts, which the United States Department of Agriculture defines as “a low-income census tract where a substantial number or share of residents has low access to a supermarket or large grocery store” (USDA). Fresh food can be very expensive in the city and for those in the low income bracket it is often more important to get as many calories as possible. Aquaponics could provide a low cost solution with very little upkeep cost that could run for much of the year, if the conditions are right.

The hanging growing beds should go into the window, but the fish tank can be placed anywhere it fits. It could go under a counter or sink. Several windows could be linked to a larger tank.

The wooden ladder frame fits snugly into the window so that the growbeds don’t tip or fall out of the window. Try to get the closest fit possihble while allowing for easy installation and removal.

When deciding the distance between the grow beds consider everything that might be grown. There should be at least 12 inches between the top of one bed to the bottom of the next.

The frame shouldn’t block much if any light access to the window.

View from the right side

The gutters tilt in opposite directions so that they drain into each other while the water gets the maximum amount of time to be filtered by the roots. A wooden ladder like frame is build to hang the gutters on.

These drain pipes reduce the splash from the falling water.

Water returns to the tank

Water travels up the piping to the top growbed

View from the back

The System The physical system can be broken into three parts: the fish tank, the filter and the growing bed. Small systems can use the growing media in the grow bed as a filter. Larger systems need dedicated filtration to properly handle and process the high amount of waste. They can include a combination of different filter types. Settling tanks, which should be drained regularly, allow for the large and heavy particles to sink to the bottom of a bucket or barrel. The liquid effluent can be applied to plants, but should be diluted in water first to ensure that the plants aren’t burned from high levels of certain nutrients. Filter pads and bead or sand filters serve as a home for helpful bacteria and are paired with some kind of aerator to give the bacteria the oxygen they need to process the ammonia. Smaller systems can use a variety of growing media as filtration, though it allows particulate to settle in the bottom of the growing beds. This isn’t a large problem with small systems because it isn’t normally that difficult to clean out the beds. When selecting media types, there are several variables that one should take into account. First, the weight of the media. This can rule out most local stone as media if the support for the growing bed isn’t built to handle the weight. Second is the pH of the media, which can also rule out local stone. Media with a pH that isn’t neutral can be used, but consideration must go into plant and fish selection if there isn’t an additive to bring it within acceptable levels. Lastly one should consider the lifespan of a particular growing media. Some media, the most utilitarian, can be reused indefinitely while other have a limited life span. Unique traits of media should also be considered, including things like sustainability and the shipping distance. The growing beds themselves are designed for whatever type of system is used to channel the water to the plants. Raft systems float on water, drip systems don’t require much depth for roots. Flood and drain systems are typically recommended to be about a foot in depth, but shallow rooted plants don’t need it. Nutrient film technique has water running only on the bottom of a channel but the roots are in danger of drying out and dying if the water stops. The design of the growing bed depends upon how the plants will be watered. The fish tank requires far less design because it remains simply a container for the fish to live in. Many fish like to be undercover and darkness makes it feel safe for them. The ratio of fish to the gallons that the container holds is important. The system shouldn’t put undue stress on the fish through closed quarters or on the filtration system and what the plants can filter out. The total grow bed volume to fish tank volume should be 1:1 for normal systems and between 1:1 and 2:1 for more intensive systems. It is good to start out with an equal ratio because it is more forgiving. The welfare of the fish is important, they are living creatures and should be given the appropriate level of care. The principle of the systems is also composed of three parts: the fish, the bacteria and the plants. The fish are fed and create waste. The ammonia in the waste is consumed by the bacteria and they output nitrogen that is useable by the plants. The plants take up the nitrogen and other nutrients from the fish water, cleaning it. The water is then returned to the fish and the cycle starts again. However, aquaponics isn’t a closed loop system.

Babylon is perhaps the most adaptable of the three aquaponic systems. The version pictured here is made to go into a window, any window. This system, in an average sized window, can filter a thirty to sixty gallon tank. It could be placed in several windows, expanding the indoor growin capacity of both fish and growbed space. It can go indoor or outdoors, but it needs plants growing throughout the year in order to keep the filtration high. This can be most easily accomplished indoors because it is climate controlled. The system could also be place outdoors on a fence, the side of the house or even act as a privacy screen. In this case it would be located in warmer climates or somehow protected from the elements. This system is a great show piece for aquaponic enthusiasts. It can serve as an example of the new applications of aquaponics and the potential of vertical farming. Because it utilizes very little space, whether indoors or out, it is well suited for urban settings. Like Tilt, Babylon uses gutters, 2x4’s, pvc pipes, plastic tubing, and a pump. Babylon, however, is a flood and drain system that uses a bell siphon to regulate the flow of water. Bell siphons are simply constucted automatic siphons that are used to drain water once it reaches a certain level. There are animations of how they function online as well as instruction of how to build them. The dimensions of this system depends on the size of the window it will be placed in. The 2x4 frame should fit snugly into the window, using the frame itself to hold it in place. It won’t be able to tip out of the window and instead must be lifted and slid out. The frame shouldn’t need to be attached to the window frame, but it might be a good way to further ensure the security. The gutters are hung almost normally, they should be at a slight angle towards the end with the bell siphon. Extra support might be adviseable if a heavy growing medium is being used. The gutter beds should be spaced at least 12”-18” from each other to allow enough head room for the plants. It depends on what is being grown. Water is pumped into the top growing bed from the fish tank. The water reaches a certain level, normally no less than 1/2” from the top of the growing medium before the bell siphon is triggered. All of the water drains into the next bed and the process is repeated until the water returns to fish tank. The pump that is selected should have a low gallon per minute rating. The gutter beds will take longer to fill up and the cycle of water and air exposure will be longer, ensuring good aeration.

Materials: cut 2X4 cut gutter gutter ends screws plastic tubing pump pvc pipe

Output: Nonedible Vegetative Matter ie, leaves, stems, culls

The Aquaponic Cycle

Babylon n

Plants absorb the nutrients and clean the water

Output: Edibles ie herbs, vegetables

Fish water filters through helpful bacteria

Output: Fish

Clean water returns to the fish 38

Input: Food

Closing the Loop Aquaponics isn’t a closed loop because both vegetative matter and fish are taken out of the system when it comes time to harvest. The manual input into the system is the feed for the fish. The sun and the air naturally supply plants, but the feed has to come from somewhere. The fish that are adapted to colder climates need to be able to acquire their stores as fast as they can, as they are normally predators. This can make cold adapted fish more difficult to feed because there is a limit to what can be grown to feed them. Feeder fish can be used, but some view the practice as inhuman or inefficent. There is also the danger of injury depending on the types of feeder fish, as well as the transmission of disease. There are three popular species grown to feed the aquaponic system: duckweed, worms and black solider fly larva. Only vermiculture, or growing worms, is suitable for cold climate carnivous fish. Black solider fly larva live in climate zones 7 – 10, but they have been noted outside of their reported range. Duckweed can be grown in most places, but needs still water. Vermiculture, out of the three popular feedstocks, is probably the best known. It is of particular interest because the non-edible vegetation from the grow beds can be turned into protein for the fish. Household scraps can likewise be recycled. Worms are simple to care for and, if the grow bed is a flood drain system, can be added directly to the system. Before you add any though, consider that worms produce a natural plant hormone called auxin which promotes decay and vegetative plant growth. This is good for a system that is growing just leafy greens, but not for a fruit bearing system that might include tomatoes, peppers, cucumbers and the like. Redworms are the most popular choice for a vermiculture systems because they live near the surface, grow and reproduce quickly and can eat half their weight of food waste every day. Black solider fly larve are a popular choice in more temperate regions. The adult fly doesn’t bite or sting, and often keeps the harmful kinds of flies away because they are territorial. The females lay their eggs near to decaying matter or manure. The eggs hatch anywhere from a few days to three weeks and can mature in as little as ten days. When ready to metamorphoses, the larva instinctively leave the feeding site and look for soil to burrow into. The commercial bins that have be created to capture the larva have a ramp and little catch bucket to collect all of the semi-mature, ready to consume insects. The adult stage is solely about reproduction, they don’t even have functional mouths! Because they are such efficient converters and decomposers, they are of particular interest when there is a great deal of nutrient rich material on hand. Black solider fly larva are also a popular feed for chickens. Duckweed is a pest in most places. It can be a destructive invasive if it is released into local waters with an ecosystem that hasn’t evolved to cope with it. It is very important to treat this feed stock carefully. That being said it is a very impressive source of protein for the fish that will eat it, namely tilapia. Duckweed can double itself every one to two days, allowing a constant harvest. Excess duckweed can be frozen or dried and fed to the fish when the production is low in the winter. It is adapted to slow, still waters, so it is good to have an area separate from the fish tank. They would likely disturb or overeat the plant.

The appearance of the system will change depending on what kinds of gutters are used.

The amount of water in the tank and growbeds will be more than the ten gallons that the tank holds. In flood drain systems the timer or siphon will have to be engaged thoughtfully.

The growbeds are pushed to the back to allow access to the fish for feeding and capture.

Cut through View from the left side

This is a very simple design that can have many possible iterations. Don’t be afraid to explore what can be built with materials on hand. The growbeds shouldn’t be connected to each other, and instead be connected to only itself. This allows for easier cleaning of both the fish tank and the beds as needed.

The grow beds tilt in opposite directions

View from the Front

From above, the fish tank is totally covered, maximizing light exposure

View from the top

The Containers The containers that are used in aquaponics give a great deal of character to the system. An enthusiast shouldn’t be afraid to used recycled containers or even just what they have on hand if it suits their needs. Aquaponics, and growing food in general, is about finding out what works well at an individual site. Systems have been designed around specific types of containers. Barrelponics and the IBC’s of Aquaponics are both handy resource that delve into the specifics of designing with a certain container, strengths and weaknesses, and other potential. There are kits and complete systems that are available for sale, but the price can be high for a system that you can build yourself. Intermediate Bulk Containers, or IBC for short, are a common container used for shipping liquids. They can easily be found around areas of high shipping, like cities. If used for aquaponics they must be food grade. Used containers can be purchased for around $100. The tanks aren’t always clean when purchased, but because it is food material that was previously inside, they are safe to clean out by hand. Be sure not to use any strong chemicals that would negativley aﬀect the fish or plants. Barrels are another popular option for aquaponics, and again should be rated as food grade. Large companies in the food serve industry sometimes have them on site. They can also be purchased online. Barrels can be time consuming and more expensive to work with because they are normally cut in half for use and a frame must be built to support the halves. Barrels are another good option for container needs.

Premade systems and kits are available for those who don’t want to venture into the Do-It-Yourself realm. This kit, called the Little Tokyo, is from Home Depot and available for $295 dollars. More intensive and larger systems are available for higher prices, going into thousands of dollars. If money is a driving decision maker in the aquaponic process, consider building your own for a far cheaper price.

Tilt is a small system that allows a person to get familiar with a functional aquaponic system quite easily. It was designed to filter the water of a small ten gallon fish tank, the average size for hobby fish. The system should eliminate all need for a traditional filter once it is established. This system should be kept inside beneath a window that gets light throughout the day to ensure great growth. Tilt is capable of producing herbs, greens or a mixture of the two. Tilt is ideal for introducing children and teens to the concepts of aquaponics and would make an excellent science fair or school project. Only the most basic of construction skills are required for this project. It is best thought of as a proof of concept. It won’t produce a great deal, merely because of the limited growing space, but what is planted will be healthy and bright. The system is constructed using a gutter, 2x4’s, pvc pipes, plastic tubing, and a pump. It is a modified raft system, but it could be also be adapted into a wick or flood and drain system. One growing bed or two can be used, depending on light, number of fish, weight and other considerations. The exact measurements and dimensions will change depending on the type of gutter and tank that is used. A deep gutter is suggested to increase the filtration and allow a greater reservior of water, which in turn can hold more nutrients and lessen pH swings. Water is pumped from the fish tank into a bed through flexible tubes. At the bottom of the beds is a growing media which acts as a home for the bacteria. Above the media is water and then the raft which the herbs are planted in. A pvc pipe on the opposite end of where the water is pumped in drains oﬀ the excess water. The pvc pipe is only slightly shorter than where the water level is normally. The height of the pvc pipe depends on the height of the gutter. The 2x4’s are attached to the bottom of the gutter with screws. They act as a support and frame for the gutters and make them easier to move and place. A hole the width of the pipe should be drilled within 1’ of the end of the board and gutter. This can also be adapted for larger tanks with longer gutters and 2x4’s. Weight might become an issue so a supportive frame could be build to decrease the strain on the tank.

Materials: cut 2X4 cut gutter gutter ends screws plastic tubing pump pvc pipe

Tilt

Growing Media There are many different options for growing media and selection depends on several different factors including cost, reusability, eventual disposal and weight. Propagation is normally done in rockwool or a similar material so that the seed or sprout isn’t lost in the media. Listed are a few of the many options. Expanded clay pellets are a popular choice because they can be reused very easily. The bright terra cotta color lends itself well to standing out. Water drains easily through the media and it is easy to handle. Expanded clay pellets are normally a bit more costly than other options. Perlite is formed by heating volcanic glass which then pops, creating much surface area in the form of air bubbles. It has been used in soils for long time to increase aeration and drainage. It’s inexpensive and good for wick type systems, but it dries out fast and the dry dust from the media is bad for your lungs. It is typically mixed with other types of media. Vermiculite is perlite’s other half. It comes from mica which is heated to make it expand. Vermiculite is excellent at retaining water, sometimes so much that the plant roots suffer for it. It too is inexpensive. A fifty-fifty mix of vermiculite and perlite can be used for flood and drain systems. Coir is made from the husks of coconuts, a waste product of the coconut industry. This makes it a bit more sustainable from the start, but it still has to be shipped from its origin. Coir is excellent because it can replace sphagnum peat moss, which in harvest releases high amounts of methane into the atmosphere. Low grade coir isn’t good for aquaponics because it is very fine and has a high salt content

Sand is perhaps the cheapest media available, and one of the longest used, but it can be the heaviest. Sand is a good option if price is a driving concern, but systems need to be built to withstand the accompaning weight. Also it is important to check the pH of the sand because it can aﬀect growing conditions. Lastly, sand can create diﬃculties with keeping aerobic conditions. 19

The Nitrogen Cycle The nitrogen cycle is important to all life. Plants need nitrogen for their chlorophyll, to regulate their growth, their structure and in the roots to help take up nutrients. Animals get the nitrogen they need from plants and most plants get the nitrogen they need from bacteria. Legumes are the exception, as they have nodes on their roots that harbor nitrifying bacteria. There is a great deal of nitrogen in the atmosphere. About 80% of it is made up of molecular nitrogen, N2, but it cannot be utilized by plants or animals at this stage. Only nitrogen fixing bacteria or lightning can change it to a useful form. Most nitrogen is fixed by bacteria which live in the soil. The N2 changes into NH4 and NH3, ammonia. The ammonia can be absorbed by Nitrosomonas which changes it into NO2-, nitrites, and the Nitrobacter changes it into NO3-, nitrates. At this point plants can use the nitrogen and use it. Nitrogen at this stage, if it isnâ&#x20AC;&#x2122;t taken up by plants, can be used by denitrifying bacteria, which releases nitrogen in the form of N2 back into the atmosphere. When plants absorb the nitrogen, it can be used by animals which eat the plants. When the plant or animal dies, they release nitrogen in the form of ammonia after they are decomposed by bacteria or fungi. The ammonia then reenters the nitrogen cycle. Humans have sought ways to increase the levels of nitrogen in soil since they became aware of its importance to growing crops. Cover crops often have plants from the legume family, peas and beans. Artificial fertilizers have also been created in order to increase the levels of nitrogen in heavily cropped soils and have been supporting the increased population of the earth for some time. Artificial nitrogen production is created through the processing of natural gas, normally through the Haber Process.

The Essential Elements Plants need 17 elements to live in diďŹ&#x20AC;ering amounts. Most of the structure of plants is made up of the three primary mineral macronutrients: nitrogen (N), phosphorous (P), and potassium (K). Many people who are familiar with gardening or farming will recognize these elements as common additives to soil. There are three secondary mineral macronutrients, calcium (Ca), magnesium (Mg) and sulfur (S). These elements are normally present in soil and donâ&#x20AC;&#x2122;t often need to be added to have healthy soil. The mineral micronutrients are boron (B), copper (Cu), iron (Fe), chloride (Cl), manganese (Mn), nickel (Ni), and zinc (Zn). These nutrients can often be supplemented by adding composted material to the growing site. The three non-mineral nutrient are hydrogen (H), carbon (C), and oxygen (O). The nutrients are freely available in the air and there is no need add them.

333

Construction Foreword In the next several pages three designs are presented, described and have a general construction guide included. None of these designs have been physically built. For now at least, they exist merely on paper or in a digital format. The designs are my thoughts on what small systems could look like. Special asthetic consideration is paid to the first two because they are designed to go inside the home and be interacted with on a daily basis, and are made to be seen. The designs are ready to be constructed and adapted to each person’s individual needs and considerations. The first two systems are designed especially for the beginner or those who are unsure if they want to take the leap into larger scale aquaponics. They filter primarily small hobby fish tanks that one finds at the pet store. The fish that supply the nutrients likely won’t be edible merely because of their small size. The larger of the two systems could potentially hold edible fish, but they would be few in number. The third system is best suited to the outdoors where it can get the appropriate level of light. It is the most basic of all of the three systems, like previous aquaponic designs done by others. There is a great deal of variety in even the most utilitarian of designs. It should be viewed as a good start, or base to work from as your experience with aquaponics grows. For further designs, check the resources page at the end of this booklet. There are several good online resources that can provide further guidance. The most basic knowledge of building is assumed in the description, but help can always be found from a handy friend or relative. None of the designs requires an acute knowledge or extreme technical skill. They are meant to be accessible to people on all levels. If one of the designs is particularly striking but isn’t quite right, I encourage you to change it to fit your unique circumstances. This booklet is meant to inform and empower the reader to create their own system for the creation of a food production system. It should be personalized to create a feeling of ownership, not over just what food is eaten, but of the system itself. It is very much a change and challenge taken on by the reader who becomes a designer and a builder. Construction will include sawing, cutting, nailing, screwing, measuring and other basic tasks. Please take all necessary safety precautions and don’t use any tools, especially power tools, in a dangerous way. Wear safety glasses and ear protection when appropriate.

Legumes Atomspheric Nitrogen N2 Nitrogen Fixing Bacteria

Decomposers

Ammonia NH4 Denitrifying Bacteria

Nitrosomonas

Plants

Suggested Tool List Saw Drill Hammer Screwdriver or power drill Tape Measure Pencil, Pen, Chalk, etc. Speed Square

Nitrobacter

Nitrate

Nitrite NO2-

NO3-

The Yellow Perch Yellow perch, Perca flavescens, are a popular fish in the Great Lake region. Several universities in the region who hope to increase their growth rate and size are studying the fish. Yellow perch are typically a smaller fish that can take up to two years before they reach harvest weight in a farmed system. In the wild they can take up to 5 years to reach ten to twelve inches in length. They are still quite popular on the market with over 5.57 million pound harvested from 1990 to 2000. This number has significantly dropped from harvests in previous years, 23 million pounds from 1950 to 1970, due to concerns of low population and contamination. Yellow perch, sometimes called lake perch or ringed perch, are native to the northeastern part of North American, with their range extending south into the Carolinas and west into Kansas. They have been introduced to most of the states and are restricted in some places. The diets of yellow perch requires protein levels of between 34 and 44 percent, very similar to what trout requires. They should eat about 2 to 3 percent of their body weight per day and conversion from food to weight is about 1.5 to 2 if feed is managed well. Their natural diet normally includes insects, small invertabrates, and fish eggs. This type of perch is suitable for farming because they are a schooling fish, allowing them to tolerate higher populations and are relatively noncannibalistic. They are suited to growing in colder climates, being able to tolerate temperatures of 50 to 80 degrees, with the ideal temperature for putting on weight being 75 degrees. Commercially, perch is in high demandâ&#x20AC;&#x201D;$16 per pound of fillet at retail around the Great Lake region. Yellow perch are well known for their mild flavor and flakey white meat. Imported frozen perch fillets sell for around $4.75. Commercially it costs around $3 per pound to raise the fish with the highest cost being purchasing the fingerlings. (Hinshaw)

The Plant

Other Fish

Much aquaculture is done in warmer climates with fish species that are adapted accordingly. This limits the number of species to choose from in colder climates. There are options beyond yellow perch, but some of them have special growing conditions and most are carnivorous. Fish in temperate areas have to gain weight and energy as quickly as possible by seeking out high energy food.

The Plant is situated in an old meat packing plant in Chicago, Illinois. The aim of the Plant is to host a variety of businesses that utilize each other’s waste stream. The Plant plans to have a commercial kitchen, a brewery, kombucha tea and an aquaponic system. The concentrated fish waste, food waste and spent grain will be put into an anaerobic digester which will create power for grow lights, which service the growbed, and for the rest of the Plant. Spent barley can be fed to the fish, tilapia, as well as duckweed that is grown from the sludge of the digester. Unlike many other operations, the Plant has its grow beds inside. The growing will be mutli-floored and make use of all available space, truly vertical growing. Like the Urban Farming Guys, the Plant use IBCs as the fish tanks. The tops are cut out and the pumps are run in series. The grow beds are right next to the fish. The system is a great deal larger than what is found at the Urban Farming Guys site, and is perhaps comparable to what is found at Growing Power. The Plant breeds its own fish, taking two different breeds whose offspring are all males. This ensures that the fish are of uniform size and there are no small offspring of what is already in the tank. The growing beds are floating rafts on a deep water culture. They are experimenting with both traditional grow lights and with LEDs. The Plant is still under construction and development, but it looks to be a very promising project.

Brook Trout Aquaponics doesn’t have to produce edible fish. If a “vegetarian” system is desired it can be stocked with other species of fish.

Koi

Creek Chub

Growing Power This is one of the betterknown faces of aquaponics. Will Allen is the CEO and owner of Growing Power. His nonprofit grows their produce in the outskirts of Milwaukee. Will Allen feels very impassioned about solving the problem of food deserts and traces health ills to eating poorly. He wants to ensure that everyone has access to the same quality of food regardless of economic conditions. Community involvement and education is important and a large part of the organization is about giving tours and spreading knowledge to those who come to visit, as well as giving speeches around the country. Growing Power’s fish holding area, a trough really, is dug into the ground of their greenhouse. It isn’t totally level with the ground. There is a wooden support about a foot oﬀ the ground all the way around the trough. On top of the trough is a double stacked set of growing beds, with enough space between to let in light, but without having it so high that it is inconvenient to harvest from the top bed. Water is run from the fish troughs to the upper bed where it gravity feeds to the lower bed before returning to the fish. The watercress and pea gravel—that is used as the growing medium—are used as filtration. There is little evaporation occuring in their system, they only add water once a month. Duckweed, food scraps, worms and black solider fly larva are all used to feed the fish. Growing Power raises 5000lbs of worms oﬀ of food scraps and compostables. They follow the ratio of one fish per one gallon of water. They grow two types of fish, lake perch and tilapia. The tilapia mature in six months to a year and the lake perch in a little over a year. The water is kept at a constant seventy degrees. This type of system is very vulnerable to power outages, during which they would lose circulation if there are no back generators, and water quality problems because it is such an intensive system. Growing Power has a very well established system and are very experienced with the process of aquaponics. It is a good example of what those with a great deal of experience can do.

The Science Barge

â&#x20AC;&#x153;The Science Barge grows tomatoes, cucumbers, and lettuce with zero net carbon emissions, zero chemical pesticides, and zero runoďŹ&#x20AC;,â&#x20AC;? (NY Sun Works). The Barge is an educational site that specializes in growing low impact crops in an urban setting, a sustainable urban farm. Its mission is to educate the public about issues involving sustainability in food, water, energy, and waste. The Barge can be moved down the Hudson River from where it is currently situated in Yonkers. The nonprofit project is run by Groundwork Hudson Valley. It is a popular destination for field trips that come from local schools. They want to connect students who have never seen a tomato on the vine or had the chance to spend the day on the river to know where the food that they depend on comes from. Crops are grown mostly hydroponically, sometimes with fish added to the system. The barge is powered largely by solar panels that track the sun. Wind turbines are also used, but mostly act as a demonstration. Evaporative cooling and fans are used for the greenhouses in the summer months. The barge also collects rainwater and filters water from the river. It is a very impressive technical achievement and shows what can be accomplished in farming by fully embracing technology.

The Urban Farming Guys

“A not-for-profit profit organization that exist to empower the globe with food freedom, alternate energy & sustainable community” (UFG, 1). This is a group of families who have moved from suburban homes to one of the worst neighborhoods in Kansas City. They all own homes within five blocks of each other and hope to address urban problems at their source as a living experiment. Aquaponics is only part of the issues that the Urban Farming Guys are tackling, but they have built a system that will grow two thousand pounds of tilapia in a space the size of a living room. Their initial design on their property is constructed out of IBCs, intermediate bulk containers. They have a system with six tanks piped together with four barrels that hold diﬀerent filters. Their filtration system is very intense because they have one thousand fish in their system. They capture the fishes’ waste from the first filter barrel, a settling tank, and put the eﬄuent into a methane digester to create biogas. The next holds a media filter which catches further particulate and acts as a home for beneficial bacterial. Next is a bead filter which is aerated and acts as another habitat for helpful bacteria while improving the oxygen levels in the system. The last filter is another settling tank. The Urban Farming Guys recently sent a team to eastern India to install an aquaponics system at an orphanage. This time the main structure was barrels. The fish had a pit dug into the ground which was then lined with a large plastic banner. The barrels were cut in half the long way and then used as the grow bed which drained into the pit. The design has been growing food successfully for a while. The Urban Farming Guys have wonderful resources online including videos and a forum for questions. True to their motto, they are sharing knowledge to feed nations.