Aquaponics

The Fish That Grew Some Food in a California High School

Aquaponics

By Susan Perreault

What do you get when you cross 1,000 worms with 12 fish, 80 high school students and one yard of red lava rock? A gar-den that is virtually self-sustaining and grows food faster, taller, and lusher than in most conventional gardens.

Seniors at California State University, Sacramento, have introduced aquaponics to high school students at Luther Burbank High School in the south part of the city.

Cheyene Kenniston, Ryan Nowshiravan, Mary Xiang, and David Hill are all collaborating on this project on urban agriculture for their environmental science class. They didn’t want it to be some rote written thesis on a theoretical project, but a living working example of what urban agriculture could be for the average person.

“We wanted to make (aquaponics) more understandable for people to do themselves,” said Kenniston, one of the originators of the project.

A simple project, however, was not what the greenhouse was destined to be. The aquaponic greenhouse quickly took on a life of its own. The greenhouse is the cornerstone of one of the school’s most popular after-school programs. In addition, the seniors have given students in the high school’s special education department something unique to learn from and enjoy.

The goal of the project was simple. “We want to teach everybody about it because it’s such a great system,” said Sac State senior Ryan Nowshiravan.

In its most basic sense, aquaponics combines hydroponics with aquaculture. In aquaculture, fish or other animals, including crawfish, prawns or snails, are raised in tanks. The water from these tanks is used to water and nourish plants or seeds in adjacent beds. Ammonia is a natural by-product of fish waste. If allowed to build up in the tank it becomes toxic to the fish. Bacteria covert the ammonia to nitrites and nitrates, then plants use these by-products as nutrients. As the water circulates through the porous rock bed, the nitrates and nitrites are removed by the plants and the water is filtered back into the fish tanks clean and free from toxins. Therefore, the aquaponic system creates the perfect closed loop system for growing plants and for growing fish! Though not done at Luther Burbank High, some people also use their aquaponic systems to raise animals for food. As the fish or other animals grow to sufficient size they are replaced by younger animals and the larger are used for food.

Aquaculture has been used for centuries in conjunction with farming, and is still used today. Farmers in China have added fish to the water of their rice paddies for over 1,500 years to add natural fertilizer to the water. In 1000 A.D, the Aztecs also used fish to aid in growing crops. They grew corn and squash on islands. In the ditches around these islands they added fish and mollusks that they raised as food. As the waste accumulated it was gathered from the bottom of the moats and used as fertilizer. Think of the natural fertilizers we use today; the fish emulsion we pay for in the organic supplement aisle works on the same principle.

In the spirit of eco-friendliness—and cost savings—the Sac State seniors used as many items as they could find at the school for their project. The school had been a former FFA site, but, with staffing changes, that program was disbanded in 2008. Many items were still left, however, to give the project a healthy boost. An abandoned 25′ x 30′ greenhouse was the perfect place to house the aquaponic set-up, and former grow tables were disassembled and their wood reused to fashion two–5′ x 5′ x 12″beds. Two dusty 130-gallon plastic tanks were cleaned and became the homes for the fish that became the heart of the aquaponic system. The few items they actually purchased included two water pumps, a yard of 3/8″ lava rock, pond liner for the wooden beds, and, of course, fish.

“We started with 75 one-inch gold fish,” said Mary Xiang, Sac State student and Burbank High alumnus who suggested this school as the site for the project, “all but six of them died.”

Greenhouse
Ryan Nowshiravan addresses students in the greenhouse.

Poor fish choice and early hiccups with the measurement of the pH and ammonia levels caused the massive fish kill. However, as luck would have it, they were able to pick up three one-pound carp for free at the state fair during the summer.

“It was readily apparent after we added the carp,” said Nowshiravan, “we saw a jump in plant growth.”

The nutrient-rich water floods the grow beds approximately every six hours. The carp, being many times larger than the one-ounce goldfish, immediately increased the nutrients flowing to the system. The amount of nutrient in the water is directly related to the size of the fish. The bigger the fish, the more waste they release. The more ammonia, the more nitrates and nitrites and the more plants the grow beds are able to support. Once set up and equalized, the only regular maintenance required is feed-ing the fish, monitoring the water’s pH level, and adding small amounts of water to the fish tanks to replace loss from evaporation.

The students planted a variety of plants during the first months of the projects. Herbs, such as basil, rosemary, lemon grass and lavender did well as did kale, iceberg lettuce, tomatoes and bird pepper seeds. All the plants showed more rapid growth with the addition of the larger fish. The leafy herbs and lettuce grew in half the time they had before. That is one of the benefits of any aquaponic system.

Aquaponic Beds
Students David Hill and Cheyene Kennisten tend to the beds.

“In aquaponics, lettuce can grow in 27 days. It takes 48 days with traditional farming,” said senior David Hill. The idea of urban agriculture has taken a solid hold among these college students; each one hopes to get jobs in sustainability or environ-mental science when they graduate.

The aquaponic grow beds that started off as a college senior project have become so much more for the staff and students at the high school. When the project was first proposed by the students to the administrators at Luther Burbank High, it immediately caught the eye of teacher Aaron McClatchy.

“When someone comes to your school and offers a project for free, your answer, as a teacher, is immediately ‘yes’,“ said McClatchy. He admits he wasn’t sure at first how he would use the students’ gift, but it became readily apparent that his special education students could benefit almost immediately.

McClatchy uses the space to prepare his autistic and developmentally delayed students for life after high school. The students perform the aquaponic and garden maintenance tasks to foster independent living skills, including cooking, shopping, and self-management.

“It’s a great tool to use because there’s so many different things we can do,” said McClatchy.

His students have practiced a wide variety of tasks, from basic chores such as washing the gritty lava rock to more advanced projects such as taking the bus to the local big-box hardware store where the students bought and paid for greenhouse supplies. All of these tasks help the students with in-dependent living skills like counting, using money, and following direction. McClatchy also uses the greenhouse and the adjacent garden as a calming space for the students when they are having a bad day.

In addition to the greenhouse, other unused spaces at the school have been brought back to life. Bare ground behind the school is once again irrigated and planted for seasonal vegetables. Abandoned cinder-block bins hold compost piles over six feet high. And an old cement block enclosure—once home to a diesel tank that fed farm machinery—now holds the worms that feed the fish. All of the students are expected to add to and maintain the compost and worm piles with scraps from the cafeteria and to “harvest” the fish food—worms, solider flies and larva—by hand.

Over 80 mainstream and special education students at Luther Bur-bank High School use the aquaponic greenhouse and its adjacent tradition-al garden; almost 30 of those students do so voluntarily in the after-school program. A day spent watching these kids dig, weed, repair irrigation, and chop worm food is testament to the lure of urban agriculture.

“I just wanted to learn about gardening. It’s a good life skill and it can help you,” says senior Rovonia Delarosa Rowe. Her autistic school-mate put his sentiment about the greenhouse even more succinctly. “It’s joyable.”

Why yes, Jose, that it is.

Leave a Reply

Your email address will not be published. Required fields are marked *

[class^="wpforms-"]
[class^="wpforms-"]