Fishy Growing

Could low-water-use aquaponics systems be the future of growing?

Maybe it's due to the struggling economy, or a desire to remove processed foods from our diets. Maybe it has to do with the rising costs of fresh food and increasing efforts to reduce our carbon footprint.

Whatever the reason, home gardening and food production is increasing in popularity.

From 2008 to 2009, the number of home gardens in the United States increased from 36 million to 43 million, according to the National Gardening Association, earning gardeners a $21 billion return on their $2.5 billion investment.

Here in Tucson, a new facet of the home-gardening trend is taking shape: Avid gardeners, amateurs and curious newcomers are working together to start an aquaponics movement—a sustainable gardening practice that incorporates elements of hydroponics (the cultivation of plants in a water-only environment) with aquaculture (the raising of aquatic life, such as fish or prawns).

Casey Townsend, a master gardener and aquaponics advocate, is heading up the Tucson AquaPonics Project, a group aimed at sharing advice, information and techniques for those interested.

"It's a viable technique, just not well-known," says Townsend.

The basic structure of an aquaponics system is to have a large-scale fish tank, which circulates water through beds where plants are growing. The fish waste fertilizes and feeds the plants, and in turn, the plants clean the water so that it can re-circulate back into the fish tank, creating a closed system.

"Really, you're not just growing fish or plants; what you're really growing is bacteria," says Townsend. "What makes it all work are the bacteria, which convert fish waste to nitrites for the plants."

Tilapia are the most commonly cultivated fish in aquaponics systems, due to their ability to survive in a wide temperature range—all the way from roughly 50 to 100 degrees Fahrenheit—though there are other viable options for fish, including channel catfish, or non-edible fish such as goldfish and koi.

Beyond helping members set up their own home aquaponics projects, the ultimate goal of the Tucson AquaPonics Project is to create a truly modular and scalable system that can be installed anywhere—which can then be sent to places in dire need, such as Sudan or Haiti, he says.

For now, they're starting slow. Townsend formed the group just this spring, but he says there's already quite a bit of interest. They're holding public meetings on the first Tuesday of every month, and are still looking for a permanent venue.

Dan Twelker was one of the first members of the Tucson AquaPonics Project, and with Townsend's help, he now has a thriving aquaponics system in his backyard.

Twelker says he was inspired to start an aquaponics system because the idea of growing food locally—and therefore using less in fossil fuels to ship food across the nation—was appealing to him.

He's currently got a system that supports 80 tilapia and four growing beds, each about two feet by four feet.

The current over-fishing of the oceans is another factor that led Twelker to try aquaponics, rather than just the standard in-ground garden.

"We, as humans, are putting a strain on ocean life by over-fishing," he says. "Every little bit we can do helps."

One of the big draws to using an aquaponics-based system, rather than traditional in-ground gardening methods, is the vastly decreased water use. Twelker says that depending on which studies you look at, an optimized aquaponics system will use only 5 to 10 percent of the water that traditional in-ground methods require.

This low-water-use, modular type of system makes aquaponics an attractive proposition for not just backyard gardeners, but for entrepreneurs looking to create larger, community- and commercial-size systems, like husband-and-wife team Stéphane Herbert-Fort and Stephanie Cortes.

The two have started up Local Roots Aquaponics (, and hope to start selling modular systems, ranging in size from a "patio" system for a small family to a system that can support several families, within the next few months. A small system should cost less than $1,000, says Herbert-Fort.

Local Roots Aquaponics will be focused on creating systems that are as low-energy, eco-friendly and organically focused as possible, says Herbert-Fort.

They're using high-density polyethylene plastics for all of their tanks and piping, which don't leach like PVC and are approved for potable water use. They're also attempting to grow their own fish food, like water lettuce, duck weed and algae, to avoid needing to use commercial fish food—which is often made from fish and contributes to the over-fishing problem, he says.

Herbert-Fort also cites the low water use of aquaponics systems and the ability to create modular, scalable systems as benefits over more-traditional methods of gardening.

"We want to convert people to think that this is how we should farm in the desert, or anywhere," he says.

Many of the existing aquaponics companies and organizations are in tropical climates, says Townsend, and one of the goals of the Tucson AquaPonics Project is to reach out and share knowledge with people and organizations experienced in creating successful systems.

"There's a lot of potential right here in Tucson," he says. "We can share knowledge and work together to perfect these systems. Aquaponics is still in its infancy. It's still a brand-new art and science, and we don't know a lot, especially in a climate like Tucson."