Aquaponics? At Green Acre Organics, it's organic gardening combining hydroponics and aquaculture

Aquaculture + hydroponics = aquaponics. It's a most intriguing way to grow food.
Published May 5 2012
Updated May 7 2012

As her once-thriving construction business dried up after the crash — as she found herself spending more of her days laying off employees and fighting with customers to get paid — Gina Cavaliero spent her evenings searching the Internet for a recession-proof business.

She was looking for something, anything, that would not vaporize with a market downturn. Finally, along with business partner Tonya Penick, she decided that when the going gets tough, the tough need to get growing.

"What's more recession-proof than growing food? You always have to eat," said Cavaliero, 43.

Almost two years ago they opened Green Acre Organics, a commercial farm that employs a relatively new agricultural method called aquaponic gardening.

"Now I get to grow food and feed people. This is so much more rewarding than construction," said Penick, 40.

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Aquaponics is a blend of two farming techniques — aquaculture and hydroponics.

Plants raised in the soil-free method known as hydroponics can grow twice as fast as those in the dirt, but traditionally consume large amounts of chemical fertilizers.

In aquaculture — basically fish farming — the problem is treating the large amounts of animal waste.

But when the two practices are combined, the water is filtered by the plants and the plants are fed by nutrient-rich water created by the other product — living, swimming tilapia.

"It's the best of both worlds," said Sylvia Bernstein, author of Aquaponic Gardening: A Step-By-Step Guide to Raising Vegetables and Fish Together.

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There are no fields at Green Acre Organics, on a quiet road a few miles east of downtown Brooksville, just greenhouses that, with their construction skills, Penick and Cavaliero were able to build over the past two years.

In the biggest of these are four large blue tanks and a series of tubes and pipes. Most of the rest of the area is covered with vibrantly green plants growing in a series of beds.

It seems high-tech, mysterious and quiet.

That is, until feeding time. The corner of a lid is lifted, a scoop of fish food is tossed in, and the dark water comes alive with swishing tails and arching fins.

Blue tilapia can grow to more than 3 pounds. And the fish generate gallons of highly efficient fertilizer, which is the key to aquaponics' chemical-free productivity: water from the fish tanks circulates under and over plant beds and back again.

The first stop is on a long bed filled with gravel. This is home to thousands of red wiggler worms that eat the fish effluent, metabolize it, and turn it into a rich, dark poop that plants can easily absorb.

The water seeps through these beds, collecting nutrients from the worm castings, and distributing them to other plants as it flows through a series of successively lower plant beds. In these, the roots poke through holes in plywood panels and spread into the enriched water.

After passing under these roots, the water comes to a small pump that moves the water back up to the fish tanks.

It is a closed loop, a self-contained ecosystem. Green Acre Organics has roughly 2,000 square feet of growing space and the capacity to grow 13,000 plants while using 90 percent less water than a traditional farm.

Penick and Cavaliero have also begun holding monthly tours of the farm, hosting instructional classes, selling custom-built systems, and have helped start a professional organization. And they spread the word that an aquaponics operation can be used to raise a variety of freshwater fish and be as large as Green Acre Organics, or as small as a 10-gallon aquarium with a 2- by 4-foot bed.

So Green Acre Organics is growing — not only lettuce, kale, celery, radicchio, eggplant, green peppers, heirloom tomatoes and herbs — but in the size and scope of its business.

"We're a part of the farm revolution. We'd like to see an aquaponic garden in everyone's back yard," Cavaliero said.

Among the potential converts are Gary and Valerie Oakley, who attended the farm's monthly tour while on holiday from their home in the Cayman Islands.

"Everything's imported in the Caymans and very expensive," said Gary, who added that he and his wife are researching the feasibility of starting a small commercial farm.

John and Patti Krueger drove from Auburndale to see an aquaponic farm in operation.

"Each of our 17 tomato plants that we have in our garden take a gallon of water every other day. It just seems like there has to be a better way," said John, who added that he and his wife are thinking of starting an aquaponics garden on their back porch.

"We just want to start small and see what happens," Patti said.

• • •

Aquaponics does have one pitfall. Most large vendors, including Walmart and Publix, avoid selling crops grown this way for liability reasons.

The big hangup is the fish effluent: it's classified by independent food safety auditors as raw manure that needs composting.

Proponents say that the usual food-borne pathogens such as Salmonella and E. coli do not grow in fish waste.

"I've been working with aquaponics for a number of years and I've never seen nor heard of a food safety issue," said Richard Tyson, the Orange County Extension commercial vegetable specialist who wrote his doctoral dissertation on aquaponics.

"These are antiquated (standards) that need to be updated for new farming methods. What is true for cow and chicken manure is not true for aquaponics," Tyson said.

• • •

It's perfectly legal to sell food raised by aquaponics on a small scale. And because Cavaliero and Penick are convinced of their food's safety — "This form of agriculture is so new that the traditional laws simply do not apply," Cavaliero said — the rules suit their business model perfectly.

They have no intention of selling to big vendors or going through the expensive process of seeking organic certification by the Agriculture Department.

Though they still haven't figured out how to sell fish at prices that compete with cheap imported tilapia, they can offer chemical-free vegetables to local vendors at a reasonable cost.

"Our prices are right in the middle — not as much as certified organic, but not as cheap as factory-farmed produce," Cavaliero said.

"Our motto is 'you don't have to be wealthy to eat healthy,' " said Cavaliero, who was interested in eating healthy but found the cost of organic produce prohibitive before she started growing her own.

Before starting the farm, she and Penick often drove to Tampa to buy locally and organically grown vegetables, Cavaliero said.

"I just thought, this is ridiculous. I started to ask myself, 'how can I be part of the solution?' "

Now she knows.