"Honey, Why Are Those Fish Swimming in Our Garden?"

If you love the idea of gardening but feel you could use some help, try an aquaponic system—and let fish do the work for you.

April 5, 2010

Instead of swimming around aimlessly, your goldfish could help your garden grow.

RODALE NEWS, EMMAUS, PA—Looking to produced more of your own food? While you may not have enough square footage for dairy cattle or even a chicken coop, you probably have the space, either indoors or out, for a fish tank or fish pond. If so, you're halfway to an aquaponic garden, which allows you to grow animals and vegetables in one harmonious ecosystem.

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THE DETAILS: Aquaponics is a type of farming that combines hydroponics, or growing plants in water, with aquaculture, or fish farming. With hydroponics, plants must be fertilized with a chemical solution, which is why the USDA has yet to certify any hydroponic farms as organic. As for aquaculture, one of its biggest drawbacks is that all the nutrient-rich fish waste in fish ponds has to go somewhere, lest it poison the fish. The perfect solution? Aquaponics, which allows gardeners and farmers to use fish waste—rather than chemicals—to fertilize their waterborne plants.

It's essentially an organic way to feed a hydroponic garden, says David Epstein, president and CEO of Earth Solutions Inc., a company that makes home-based aquaponic systems. "Nature works best when we work less," he says. "People have taken what's natural—the normal ebb-and-flow tide of rivers and lakes that naturally fertilizes the shoreline—and artificially divided it into hydroponics and aquaculture. In trying to maximize efficiency, people ended up increasing the labor involved." With aquaponics, the only real labor is feeding the fish and harvesting your crops. The ecosystem takes care of the rest.

Keep reading to learn how you can build an aquaponic garden at home.

WHAT IT MEANS: You don't need tons of space to set up an aquaponic garden; simply make it as large or as small as you have space for. Some of the more elaborate home-based aquaponic gardens take up the same space as a backyard greenhouse and house 70 to 80 large fish. Whereas the smaller type of system Epstein sells is essentially a raised garden bed that sits atop a fish tank, with a pump circulating water from the fish tank to the garden. The crops grow in a small bed of gravel, and as the water moves from the plants down through the gravel, it’s filtered and pumped back into the fish tank. Thus, no water wasted. Epstein says you can start plants from seed in the gravel, or buy seedlings as if you were planting them in soil.

Interested in giving aquaponics a try? Here are a few things to consider:

•  Choose your crops. Regarding what you can grow, you're only limited by your imagination and the space you have. "Lettuces, strawberries, basil, parsley, plants like chard—they all do well in an aquaponic system,” says Epstein. Herbs are a good choice for a beginner. “You can grow your entire supply of kitchen herbs with a small garden bed over a 10-gallon fish tank." Larger outdoor tanks can accommodate more ambitious crops such as carrots and melons.

•  Choose your fish. Small indoor aquaponic tanks can be stocked with goldfish, coy, or any other decorative, tropical fish you'd keep in a home aquarium. If you want to get more adventurous, experiment with edible species such as tilapia, catfish, rainbow trout, even barramundi—which of course would provide both vegetables and fish for the table. Edible fish require larger tanks, in the 29 to 45 gallon range, but the fish thrive just as well indoors as outdoors, according to Epstein.

Epstein's aquaponic systems and other like them are sold online through Amazon.com and HomeDepot.com. Epstein’s start at $289 for a small 12- by 20-inch bed you can place over a 10-gallon tank, which you need to purchase separately. The largest bed-and-tank combinations go for about $3,000 for an entire system. Or you can build your own thanks to a growing number of resources, such as the Aquaponic Journal published by an aquaponic farmer in Wisconsin, or www.backyardaquaponics.com, a website run by several aquaponic farmers in Australia, where the technique is quite popular.

If you have kids, consider asking their teachers or principal to start an aquaponic system in school. Epstein says the Los Angeles Unified School District recently ordered several dozen systems to place in classrooms as a teaching tool. "People like these from an educational standpoint," he says. "They teach kids the concept of gardening. It's hands-on fun, and the kids learn how an ecosystem works."