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Aquaponic farming saves water, but can it feed the country?

June 22, 2015 at 6:25 PM EDT
Aquaponics, a system of farming that uses no soil, also uses far less water than traditional agriculture. But while the technique is gaining attention, it remains a very niche way to grow produce due to economic limitations. Special correspondent Cat Wise reports from Half Moon Bay, California.

JUDY WOODRUFF: An ancient farming technique that uses far less water than traditional agriculture is getting new attention around the country, especially in the drought-stricken West.

The NewsHour’s Cat Wise has our report.

CAT WISE: In a greenhouse nestled in a valley near Half Moon Bay, California, farmer Ken Armstrong is tending to his herd, some 3,000 fish who are key members of a complex ecosystem that also includes some helpful bacteria and these floating leafy greens.

There’s not a speck of soil to be seen here at Ouroboros Farms, where Armstrong and his colleagues are growing produce with an agricultural system called aquaponics.

KEN ARMSTRONG, Owner & Founder, Ouroboros Farms: The fish are the integral part of a system. They provide the nutrients for all — for the system. So we feed our fish an organic fish feed. And this is — becomes the nutrient base for all of our plants.

So, the food that the fish eat becomes usable nitrogen by the plants. And so the fish are actually the engine of growth. This is where all the magic happens.

CAT WISE: In other words, the fish waste becomes food for the plants, and the plants in turn clean the water for the fish. It’s a delicately balanced system that requires some basic science to master.

KEN ARMSTRONG: I had to do a lot of research, and there was a little bit of trial and error. We lost a few batches of fish before we finally just figured out how the whole system worked well.

CAT WISE: Armstrong isn’t the first farmer to try aquaponics. It’s a method that’s been around for a really long time. It’s believed the Aztecs and ancient cultures in parts of Asia fertilized their crops with wild fish.

Today, aquaponics is being used in a number of countries, from Myanmar, to Peru, to Germany, even on rooftops in Gaza. In the U.S., a small number of backyard hobbyists have been tinkering with the system for years. But, until recently, it hasn’t been tried on a large-scale commercial basis. Now, the team at Ouroboros Farms, and a handful of other operations around the country, are giving it a go.

JESSICA PATTON, Ouroboros Farms: This is like a conveyor belt of produce.

CAT WISE: Jessica Patton’s official title on the farm is plant whisperer. She harvests 2,000 heads of lettuce a week, which sell for about $3.00 each, roughly the same cost as an organic head of lettuce. She says the plants here grow about a third faster than if they were grown in soil.

JESSICA PATTON: In traditional farming methods, the plant expends a lot of energy at sending out a taproot and trying to find nutrients. We have a constant nutrient system underneath the plants. The plants are able to expend their energy growing, instead of sending out energy in a root mass.

CAT WISE: Faster plant growth is one of the benefits of aquaponics, but the other big one is water usage, a critical issue in drought-stricken California, where a large percentage of the state’s developed water goes to agriculture. Some in the aquaponics industry claim their systems use about 90 percent less water than traditional soil farming.

KEN ARMSTRONG: There’s almost no evaporation in these systems. The only usage of water comes through transpiration, what the plants actually utilize.

Comparing to soil agriculture, plants can only take up water through the tips of their roots, so you need to soak the top layer of soil in order for the water to get down to where the plant can actually use it. So, that top layer of topsoil, all that water just evaporates.

CAT WISE: The 60,000 gallons of water at Ouroboros have been circulating for a year. Weekly top-offs are needed, but the overall water savings for each plant grown is significant. For example, Armstrong says a mature head of lettuce in his operation uses about a gallon of water over the six-week growth cycle, far less most lettuces grown in soil.

JESSICA PATTON: That is amazing.

CAT WISE: But, for all its benefits, aquaponics does have its limitations. It doesn’t make sense economically to grow certain staple foods, like wheat and corn, given the infrastructure of the system.

And a big drawback is cost. Armstrong, who is independently wealthy, spent a quarter-of-a-million dollars to build the system. In March, after three years in operation, he finally began to make a profit. But he thinks it will be another three years before he will make his money back.

FRED CONTE, University of California, Davis: We are a long way off from aquaponics taking the place of traditional agriculture.

CAT WISE: Fred Conte from the University of California at Davis, one of the country’s top agricultural schools, studies aquaponics. He says the drought has piqued interest in the technique, but it remains a very small, niche way to grow produce.

FRED CONTE: Scaling up that system is the difficult part. Once you get beyond about an acre of production, then it moves out from the family-type operation. You’re hiring more and more people and costs go up.

Right now, it’s a high-end business, all the way from the production of the operation into the consumption of the vegetables as well.

CAT WISE: A high-end business with a Tesla delivery vehicle. Armstrong hand-delivers most of the farm’s weekly orders to a small number of upscale Bay Area restaurants.

One of his top customers is Christopher Aquino, executive chef of Viognier Restaurant in the city of San Mateo.

CHRISTOPHER AQUINO, Executive Chef, Viognier Restaurant: Oh, these are awesome. Yes, the smaller the better. Yes, like that’s the size we wanted.

CAT WISE: Aquino says the superior quality of the leafy greens he gets from Ouroboros Farms is only one reason he buys from them.

CHRISTOPHER AQUINO: The reason why we have gone with Ken is because his water usage is significantly less than most other farms. Had to be conscious about my water usage, and not so much of how much water is going down my drains. How much water are my farmers using?

CAT WISE: Armstrong says that now that his farm is up and running, he intends to spread knowledge about aquaponics around the country.

KEN ARMSTRONG: I honestly believe that this is the future of farming. You can do them anywhere. You can do them indoors, outdoors, in warehouses, on rooftops, empty alleyways, empty parking lots. So all the space that’s being underutilized in urban areas could be transformed easily into an aquaponics system. And then you’re providing really clean, healthy produce for the local community.

CAT WISE: Later this summer, Ouroboros Farms will host a four-day workshop for those interested in starting commercial aquaponics operations. Several hundred are expected to attend.

For the “PBS NewsHour,” I’m Cat Wise in Half Moon Bay, California.