Brewster Kahle – Homemade Aquaponics

What if we could grow our food locally? As an extreme, what if we could grow all the food we need in our own back yards? While maybe not what most people would want to do, if a few people in each community were to grow their own food, then others would learn from them and could apply their new knowledge to their buying decisions to effect large-scale change. Also, larger but still small-scale farms could evolve on the outskirts of towns and cities bringing many of the benefits of connecting citizens to their food. I set out to try a thought experiment — what if we could feed ourselves from a Backyard Family Farm? I believe it now possible and even desirable. Best yet, it may not be overly difficult to build some test environments.

What would it take to make a successful backyard family farm?

• One hour of work a day per person or less,

• Supports all the food of a typical family of three,

• 1/8 of an acre,

• Vegetables, fruit, fish, chicken, maybe grains,

• Low fuel costs: almost completely solar powered for heat, electricity, and growing,

• Low groundwater use: almost completely run off of rainfall or maybe gray water use, and

• Applicable in many geographic areas.

If we could accomplish most of these goals we could have a replicable model for food production and food production awareness. To say a bit about where these goals come from and how they might be achievable lets start with the first one, which is the labor target.

Talking with friends that have gone into organic farming, they have said that it’s hard work and has led to burnout. We have to make this easy enough to not be a full time job. What if it would take 1 hour per day, per person to tend one’s garden? Since families average about 1/10 of their income on food, and 1 hour is 1/8 of the average workday, then we would be spending about the equivalent amount of our time on the farm, rather than the earning money needed to buy food at a store. An hour a day would keep one in contact with ones food, get some productive exercise, and build confidence in self-reliance. Even if one loses one’s job, one would still have food.

Supporting all the food needs of a family of three is attainable, but Americans have grown accustomed to a very wide variety of food choices. So if this farm were able to achieve the goal, but the family could afford to eat out occasionally or knows other farmers for swapping, we could achieve similar levels of diversity we currently enjoy. I have heard there is an active barter system among farmers at farmers markets. If applied to backyard family farmers, this barter system would build relationships that can further secure our food supply against shortages or crop failures.

An eighth of an acre is a very small farm. A 75 x 75 foot area is about 1/2 of the suburban plots in many areas. But we have reason to be optimistic. The aquaponic system does not grow grains and requires external inputs, but it produces much more than a family needs.

A “typical family of three” is used here rather than the “family of four” because the average United States household size is, in fact, now only 2.61 people. There is nothing in the Backyard Family Farm that would not work for more or fewer people, but some of the parameters might have to change.

Further, many lands lend themselves to better farming of certain plants than others — is there a way to grow a variety of foods in one place, and then can we use a wide range of locales for these farms? By following some of the techniques already explored, the answer is yes. Constructing a green house around our farm would make it more applicable to more environments.

If our family is to have the regulation amount of protein from fish alone, then we need approximately a pound and a half of fish per day. This can be supplied by a tank that is 10 feet by 75 feet of Tilapia. Tilapia is the second most farmed fish in the world, after carp, and can grow in small-scale ponds like this. Unfortunately, some regions such as Northern California, regard it as an invasive species, so it cannot be farmed everywhere. Different fish species can be farmed, and farmed together. Polyculture fish farming has worked for mixing tilapia and catfish, tilapia and carp, tilapia and shrimp, and catfish and paddlefish. Maybe we could have a large number of different fish in the pond. This could keep the families interest in caring for the fish and in eating the fish.

Chickens, ducks, geese could add a source of eggs, meat, entertainment, as well as, fish food. Keeping chickens in greenhouses has the added benefit of helping with temperature regulation. Where factory farmed chicken is slaughtered sooner, “free-range” chickens are often slaughtered at 14 weeks. A productive hen can lay 300 eggs a year, so maybe the farm should have 2 chickens. Chicken waste is commonly fed to fish in pond-based fish farms in Asia.

On the subject of water use, this farm might be able to live just off of rainwater! If this were true, this could be a huge boon in water conservation as current farms use rivers and underground aquifers extensively. To see if this would work here, lets do a few calculations. The average California rainfall is 17 inches per year, 20 inches in San Francisco, 35 inches in the farm country north of San Francisco. The fish tank could be used as a cistern to catch the rain. Assuming the middle of the rain estimates, we would get about 200 gallons/day just from rain. Then there is amount of recycling of household gray water that could be done. Based on the water-use of the larger-than-needed aquaponics system, running our farm on 200 gallons could be feasible.

While some electric power will be needed for pumps and controls, the majority of the energy can come directly from sunlight for the plants and keep the farm warm. It is plausible that this farm would not need much external fuel.

So it is plausible that a Backyard Family Farm could achieve our goals and be a success. There would be significant research and development needed, but it seems possible. The benefits to the individual family, the community, and if copied, the world are significant.

For instance, we might be able to help our current environmental degradation by going to an intensive farming structure like this. The current land used to feed a US family is about 6 acres. If we even reduce this to one acre, then the US could generate $200 billion a year in export revenue (about 10% of the total federal tax revenue), or we could return 600 million acres to prairie and forest — the equivalent of 3 times the Louisiana Purchase.

Based on pioneering work on sustainable and small-scale agriculture we could have a system that can feed ourselves, educate ourselves, and return most of the land and water resources to their pre-human equilibrium. Lets eat.

My backyard family farm adventure…. started with a thoughtful friend saying something I had never heard before: “Eat vegetarian fish.” Upon thinking about this, my world unraveled. Eventually it raveled again. (Is “raveled” the opposite of “unraveled”?) Well anyway, it came back together again leading to the idea of a Backyard Family Farm Kit. While still in its early chapters, I would like to bring this possibility to your attention.

In the summer of 2007, I visited my friend Jesse Ausabel on Cape Cod to discuss building open libraries in the digital age, but as I was leaving I asked him about the state of life in the seas. He is a good person to ask this particular question because he started a project in the year 2000 to count all the fish in the sea, called the Census of Marine Life. As if that weren’t hard enough, he wanted to know how these populations change over a decade. The project now involves thousands of people from 80 countries. It is from this project that we have seen a stream of stories about the virtual disappearance of different kinds of fish, such as the Atlantic Bluefin Tuna.

When I was growing up, tuna was the “chicken of the sea.” Now it is being massively overfished. As Jesse put it, it is a bad time for any fish that is either large or delicious. Almost all fish that are large or delicious are in serious decline; many populations are down over 90% from a century ago. Jesse Ausabel is the kind of scientist who thinks hard about what he says and one of those people who, if I listen carefully enough, and I think hard enough about what he says, it leads to more interesting insights. The problem, he said, is that people are eating too much fish. From a personal perspective, I remember when I was growing up that salmon and lox were expensive delicacies but now they are served in vast quantity. Salmon has been available for under $5 a pound at Wal-Mart. Jesse said that commercial fishermen are now “hoovering up the seas” with vast trawling nets.

Always the technology optimist, I asked about farmed fish. I had heard of problems with the vast salmon farms off the coast of Chile — the environmental impact of the fish waste, the problems with the farmed fish escaping and affecting the native populations, the antibiotics used on diseased farmed fish thereby exposing unprotected native fish to diseases and wiping them out… But I had recently been fed some fish presented by a dot-com millionaire from some venture he was funding to farm fish in pens in the deep Pacific Ocean and this was touted as a great solution. Can we find our way through this overfishing wild fish problem with farmed fish?

He said farming fish might work, but he pointed out a problem that I had never heard of before — he said that most farmed fish eaten in the United States are carnivorous. They eat other fish. These other fish, such as anchovies, herring, and sardines, are generally caught in the wild to be fed to the farmed fish. So now we are harvesting wild feeder fish for the farms. Diminishing those wild fish populations ripples through other wild fish populations, and we have the problem he was talking about. Three pounds of feeder fish are used to fatten a salmon by one pound. And a 3-pound fish yields roughly one pound of fillet. Therefore, approximately nine pounds of sardines are needed to make one pound of fish fillet in the supermarket. Jesse said that either we have to trick our carnivorous fish into eating tofu (soybean flavored with fish) or, as he put it, we have to “eat vegetarian fish”.

I was puzzled. I had not heard someone ever talk about vegetarian fish before. He said that carp, catfish, scallops, tilapia and others are vegetarians — instead of eating other fish, they eat algae or other kinds of muck that is lower on the food chain. Farming these types of fish might have other problems, but they won’t eat the world out of wild fish. I thought about the land animals we eat, and that they are all vegetarians — cows, chickens, pigs, and turkeys. There are some people that eat dogs and cats, which are carnivorous, but they’re not the majority. This was intriguing to me.

So I started to learn more about the food I eat. I read Fast Food Nation, Omnivore’s Dilemma, and Grow More Vegetables; watched SuperSize Me, Future of Food, King Corn, Drop of Life, Raw for 30 Days, and An Inconvenient Truth. The issues being raised are large, but seemingly interrelated. Excess corn production, deforestation, global warming, obesity, oil dependency, clean water shortages, and depletion of the soils. Our decision-making structures over the last century have led to vast increases in population and ecological strain.

The commoditization of food and the mass farming of the “green revolution” may have created much more food, but it also may have had an unattended consequence. Most of us have lost touch with where our food comes from and how our choices in our supermarkets lead to rippling effects that are reshaping the biosphere. Most of the grains we eat in the United States come from almost unpopulated farms that many of us will never see except from thirty thousand feet in the air. The vegetables and tubers come from farms that employ migrant workers that most of us will never meet. In other words, we do not grow our own food nor do we know who does, which could be a reason many of us eat too much and many unhealthy foods.

Maybe we could change that. Maybe we could get back in direct contact with food production by developing a locally self-sustainable food system that would not require a radically different lifestyle from that we have come to enjoy. Inspired by the experiments in the 1980’s at the New Alchemy Institute on Cape Cod, I wondered: Could we make a “backyard family farm” that would feed a family of three in an ecological and economical way?