Were Your Vegetables Fertilized by Elephants?

Zoos across the country are turning animal poo into piles of brown gold.


A 50-foot-tall mountain of composting manure shades a yellow, rust-speckled 1980s tractor as the sun rises over Sweetwater Organic Community Farm. Farmers, community members, and volunteers laugh as they walk between rows of production beds, harvesting the vegetables bursting from the mounds of nutrient rich soil.

As both seasoned and novice hands harvest squash, peppers, and eggplants from across the six-acre farm situated among the suburbs of Tampa, Florida, one cannot help but notice the dark loamy earth clinging to pickers’ boots and caking onto their hands.

And Sweetwater puts that soil to great use. The farm sustains itself primarily through a community-supported agriculture (CSA) program, an on-site farmers’ market, and volunteer power. Sweetwater also provides educational field trips for local schools, apprenticeships for aspiring farmers, and programs to assist low-income neighbors.

Soil of this quality isn’t easy to build, explained Jenise Carr, one of two farm managers at Sweetwater. “It takes years of frequent soil amendment to transform Florida’s sandy ground into the nutrient-dense soil we need to grow big, healthy crops,” she said. Adding all that compost not only adds nutrients, but also helps the soil to retain moisture. “When you combine that with all this Florida sun, you have everything you need for a great harvest,” Carr added.

However, these materials are not always easily accessible in large quantities if a farm doesn’t raise animals. And so Sweetwater’s farmers turn to another community pillar to help: Waste from the elephants, chimpanzees, koala bears, and other animals at the nearby Lowry Park Zoo.

“We get one or two trucks of manure once or twice a week,” explained Yvette Rouse, Sweetwater’s executive director. The free manure is then mixed with woodchips, courtesy of a few local landscaping and tree removal companies. The waste is then flipped five times over the next 15 days to meet the U.S. Department of Agriculture’s standards for compost use, and then put to work helping Sweetwater—and other local farms—grow food.

Piles of Poo Transformed into Public Good

By partnering with Lowry Park Zoo, Sweetwater and a handful of smaller operations in the community that get free zoo poo have pulled off a neat trick. Not only is Sweetwater saving $3,000 a month in fertilizer costs—which allows them to offer half-priced veggies to lower-income community members—but the Lowry Zoo is also saving tens of thousands of dollars a year in waste-management costs. The money saved “frees up funds for free kids admission days and special events like our Zoo University speaker series,” said Caroline Pace, the zoo’s commissary manager. “We also use the compost to fertilize our gardens and bird habitats.”

The average elephant produces 120 pounds of waste a day and Lowry Park has four. According to Pace, the zoo donates around 50,000 pounds of waste every week to the neighboring farms.

The partnership between Sweetwater and Lowry Park dates back 25 years, and stems from a friendship between Sweetwater founder Rick Martinez and the zoo’s CEO at the time. Over drinks, the two men realized they both had a resource that the other could benefit from. And, just like that, a symbiotic relationship was formed.

Zoo poo’s benefits stretch beyond the boundaries of Sweetwater’s fields or the walls of Lowry Park Zoo. The Sustainable Living Project, another Tampa-based urban agriculture project benefiting from the donations, is able to use its savings to offer therapeutic garden services to veterans and other underserved communities. According to Will Carey, the farm’s founder and manager, the donated compost “saves the farm thousands,” making their rehabilitation programs possible.

Turning Zoo Waste into Gold Nationwide

Lowry Park Zoo is not the only zoo to turn its waste into brown gold. Zoos in Seattle, Detroit, and Louisville, Kentucky, are composting, selling, and donating their animal poo. Seattle’s Woodland Park Zoo is selling their compost by the bucket and truck load, turning $60,000 in waste removal fees into $15,000 in additional income that is then used to improve the conditions of the animal habitats as well as other conservation efforts.

The Detroit Zoo is in the process of building an anaerobic digester to capture the methane released from the composting manure to power their onsite veterinary hospital. The effort reduces the zoo’s carbon footprint and saves the zoo a substantial amount of money in energy costs. The goal is to become “as sustainable and environmentally friendly as possible” said Gerry VanAcker, the zoo’s chief operating officer. “The energy produced by the digester is projected to save us as much as $100,000 in utility bills, and it prevents all that methane from being released into the environment.”

Despite the benefits that programs like these bring to zoos and communities, not everyone is on board. For some animal rights activists, such as Larry Rumbough with Animal Activists of Central Florida, the benefits of zoo poo do not outweigh the problems he has with the zoo itself.

“Studies have shown that animals kept in captivity suffer both mentally and physically,” Rumbough said. “They become bored and stressed, and this has serious impacts on their health.” Even when zoos do follow federal regulations regarding cage size, environment, fencing, and food, “it is still nothing compared to the freedom of the wild,” he said.

“Just because the manure is free does not make it okay,” Rumbough added. “I would never accept milk or meat from a farm that keeps its animals penned up and force-feeds them low-quality food, even if it was free. The zoo is no different.”

However, farmers like Matthew Furney, who owns and operates Generation Farms in Teton Valley, Idaho, and prides himself in the ethical treatment of his animals, argues that the farms aren’t keeping the zoo in business. Farmers who need of tons of compost can be left with few options. Commercial manure is at risk of containing toxins resulting from animals consuming feed that has been sprayed with pesticides, herbicides, and other chemicals. Similarly, commercial compost has been known to contain local pollutants that can be impossible to avoid when collecting material at such a large scale.

The bottom line is “Obtaining the amount of natural fertilizer needed to keep a farm up and running is tough, especially if you want to do it responsibly,” Furney points out. In the case of Sweetwater, Rouse said that if it was not for the zoo, the farm would have to scramble to piecemeal together the compost it needs from a variety of local horse stables, farmers, and other creative sources. As the number of compost sources grows, so do the cost, complexity, and chances for potential contaminants.

As communities continue to search for ways to improve sustainable, local agriculture, the team at Sweetwater is happy to grow their veggies with the help of a few local elephants.

Photo CC-licensed by Pauline Guilmot.

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  1. Alison Walker
    Tuesday, August 1st, 2017
    I'm very curious about veterinary medicines/supplements in zoo animals and if this is a concern for using that compost - would love any info anyone has!
  2. Imani Stefanie Foster
    Wednesday, August 2nd, 2017
    Perfect timing. Some of the gardens and farms that participate in the Grown In Detroit "cooperatively selling" arm of my organization (Keep Growing Detroit) have either had "zoo poo" from the Detroit Zoo delivered or they have picked it up themselves. Anyway, here at GID we use sustainable farming practices and promote health in nutrition by producing food in healthy soil (we do a soil test on each garden that sale with GID) without harmful chemicals, pesticides, fertilizers or GMO's. You can imagine when the gardeners shared this practice with me I was a bit concerned and plan to conduct a workshop on the best practices when it comes to using "zoo poo". Should you have any additional information, or suggestions to pass along to me about this topic I sure would appreciate it. The workshop will be held sometime in the fall. Imani S. Foster GID Market Manager, MIFMA Certified Market Manager.

    Thanks
    313-833-3872