Aquaponics links fish and veggie farming

The lush beds of lettuce, mustard greens and peppers at the Johns Hopkins Center for a Livable Future's greenhouse resemble the plants that Rick Lee of Damascus has grown in his greenhouse. Yet instead of traditional in-ground fertilizer, these plants get their nutrients from a different source: fish waste.

The plants, all floating in water, and the huge fish tanks stocked with tilapia connected to them, are part of a fast-growing field known as aquaponics — the combination of soilless plant gardening and fish farming. It's a method that's being embraced both for commercial uses and by individuals who just want to add more fresh food to their diets.


"Aquaponics offers a space-efficient method of producing food without soil, so it often makes sense in urban environments where good soil is scarce," said Laura Genello, manager of the Center for a Livable Future's Aquaponics Project at Cylburn Arboretum.

To find out more about how this method of growing food is being used, The Johns Hopkins Center for a Livable Future asked more than 800 aquaponics practitioners worldwide about their experiences. The survey found the field is increasingly appealing to everyone from backyard hobbyists like Lee to scientists and commercial producers, with reasons including a desire to grow food sustainably, for personal health, for educational purposes and as a way to increase food production in urban areas.


"They really wanted to grow their own food," said Dave Love, lead survey author and assistant scientist at Johns Hopkins Center for a Livable Future. "They also had a sense that they wanted to be more environmentally sustainable... and improve their health."

The survey also found that most of the respondents were new to the field. About nine out of 10 had five or fewer years of experience, supporting the recent surge in popularity, Love said.

Here's how aquaponics work: Water cycles between the fish tank and the plant beds. Bacteria break down fish waste into nutrients, which are filtered out by plants before water returns to the fish tanks.

"The fish benefit the plants by fertilizing the water, and the plants benefit the fish by filtering the water, which means we're not generating any waste," Genello explained.


Putting the fish directly in the tanks that house the plants is not done for two reasons. The fish tend to eat the plants' roots and that can affect the plants' growth, and it's hard to harvest fish that are hiding under a large amount of greenery.

According to the survey, the median aquaponics system held 500 gallons of water and was located in a 160 square foot space — about the size of a garage, Love said. For the hobbyists who responded, the average system measured about 100 square feet, or the size of a typical backyard garden, he said.

Systems were housed outside in the open or in greenhouses or hoop houses, inside buildings and occasionally on rooftops, Love said.

The Center for a Livable Future's aquaponics system, launched in 2012 so scientists could study and demonstrate aquaponics, holds about 3,000 gallons of water.

In addition to lettuce, mustard greens and peppers, Genello and her staff grow Swiss chard, kale, water cress, bok choi, sorrel and Tango celery almost year round in two, 8-by-18-foot floating beds and one 4-by-6-foot gravel media bed. The floating bed plants grow through holes cut from Styrofoam cooler lids.

Most of the harvested vegetables are sold at the Waverly Farmer's Market. Money made helps the center pay for operating costs like fish food, energy and seeds, Genello said.

Occasionally the project harvests fish, which are then sold through Bon Appetit, the Johns Hopkins University catering company, to restaurants like Woodberry Kitchen or the Johns Hopkins University dining hall.

Aquaponics practitioners usually eat the crops they grow on a weekly basis — much more often than they consume fish, Love said.

"They're typically eating fish on a monthly or every couple month basis, if they were at all because about half the hobbyists were not growing edible fish," Love said. "They're growing ornamental fish like koi or goldfish."

Genello added that "the income generated from the plants is generally more than the income from the fish because the plants are harvested more frequently, and the systems are designed to hold more plants than fish."

Commercial producer Ryan Chatterson said he eats his own produce every night. In 2012, the Florida resident launched his aquaponics farm just outside Orlando to promote a healthy lifestyle so that his community could get local food.

"People want to eat healthy," he said. "It's just getting them access to that healthy food."

He also wanted to practice an "ultra sustainable way of farming with a really small footprint," he said.

Chatterson grows and sells more than 150 varieties of pesticide-free fruits and vegetables, including heirloom tomatoes, kohlrabi, peppers, lettuce, strawberries, melons and blackberries, as well as tilapia and ornamental coy fish.

At area farmers' markets, his produce consistently sells out, he said. He also has a waiting list for his weekly sampler package, which includes at least eight seasonal vegetables and five or more bunches of herbs grown on his farm.

"We get people the freshest stuff around," he said.

In terms of nutritional benefits, there is no difference between food grown at aquaponics farms and food grown at soil-based farms, Love said.

Running a successful aquaponics farm takes time, the experts say, and a lot of trial-and-error.

"Aquaponics is a labor of love," Love said. "You need a little bit more disposable income than other forms of soil agriculture, you need a little bit of patience and you have to be committed to it because it does take some care and feeding."

Aquaponics supplies can be found online or at local hydroponics stores like Urban Organics in Elkridge. Systems can cost anywhere from several hundred to several thousands of dollars, depending on the size. The Maryland Department of Natural Resources also requires commercial producers have an aquaculture permit. But once a system is up and running successfully, experts like Genello and Chatterson say, the fruits (and vegetables) of the labor are worthwhile.

Back at the Center for a Livable Future's project, Rick Lee said the information gained from his visit will help him and his son, Nate, decide if they have a future in aquaponics.

For months, they have contemplated launching a system in the backyard of Nate's home in the Overlea neighborhood.

Both said they are interested in conservation, sustainability and knowing where their food comes from. And combined, they have the gardening and fish-raising experience to get started on a commercial project. Rick Lee has grown fruits and vegetables as a hobby for 25 years, while Nate owns a 55-gallon and two 70-gallon freshwater fish tanks filled with everything from Angelfish and Oscar fish to frogs.

"It's something that appeals to us," Rick said. "We're both looking for something new. [Aquaponics] is in its infancy and has a lot of growth potential. The timing is good for this."


Aquaponics findings


The Johns Hopkins Center for a Livable Future, an academic center examining the relationships among food, diet, environment and public health, surveyed more than 800 aquaponics practitioners worldwide to learn more about their production methods, demographics, motivations and experiences. Survey findings included:

• Aquaponics is practiced in at least 43 countries and almost every state in the United States.

• About 84 percent of respondents practiced aquaponics as a hobby.

• Basil, tomatoes and salad greens were the three most common crops grown.

• Tilapia, ornamental fish and catfish were the most common fish raised.

• 39 percent captured rainwater for their systems.

• 57 percent get some of their energy from renewable sources.

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