by Heather Hansman   /  September 22, 2014

“Instead of water wings and inner tubes, Dennis and Danielle McClung’s backyard pool in Mesa, Arizona, is filled with tomato plants, grape vines and wheat. There’s a chicken coop and a fish pond, and the food that comes out of the pool, from tilapia to tomatoes, feeds the McClung family of five. It’s a system that took a few frustrating failures to perfect, but now the McClungs hope to take swimming-pool farming international. When the McClungs bought the foreclosed home in 2009, the backyard was a suburban wasteland with a cracked, concrete, in-ground pool. “The real estate agent told us we had to do something about the pool, but he didn’t give us a good option,” Dennis says. “So we figured we could turn it in to a greenhouse.” The McClungs has some farming and building experience — Dennis worked on a dairy farm and at Home Depot, and Danielle grew up on small farm in Ohio — and they’d been trying to become as self-sufficient as possible. But they’d never started their own growing operation. Unintimidated, and with no interest in swimming, Dennis drew up a model and two days after they moved in they started framing up a greenhouse in the pool.

It’s hard enough to grow grass in the desert, much less greens, but the McClungs have made it work, using a tenth of the water traditional agriculture uses. They’ve turned the pool into a closed-loop aquaponic farm that they call Garden Pool. All the parts are linked — it’s almost Rube Goldberg-esque in its connections — to create an ecosystem that’s almost entirely self-sustaining and thrives in Mesa’s harsh climate. The McClungs get most of their food out of the pool (they’ll take their kids out for pizza occasionally) and they’re trying to share the wealth. They’ve started a non-profit and become authorities on closed-loop farming in arid areas. They’ve built pools in Haiti, as well as in their community, and they’ve turned their house and yard into a permaculture lab.

It starts with a pond — in their case, the deep end of the pool — which is full of tilapia and duckweed. Chickens roost over the pond, dropping excrement for fertilizer and eating the duckweed. Water from the fishpond is pumped into hydroponic beds where they grow everything from wheat to sweet potatoes in low-moisture coconut coir (A growing medium made from the fibers of the coconut husk, which holds water well in dry climates). Then the water is recycled back into the pond. Solar panels on the roof of the house power the pump and collect rainwater for the pond.

“There are outside inputs; people will say, ‘you’re getting solar energy from the sun, Dennis!’ but it’s pretty much closed loop,” Dennis says. It’s taken them a while to dial in the system. They started with container gardens in the pool, which scorched almost immediately in the Arizona heat. From there, they experimented with different kind of hydroponic setups and soil mixtures. At one point, they were keeping things cool with a giant swamp cooler. “We spent a lot of time falling on our faces,” Dennis says. “We’d put one fire out with another.” Through trial and error they’ve found that chicken excrement creates an ideal algae bloom for fish food, and that duckweed oxygenates the pond and keeps the chickens fed. They’ve learned that sweet potatoes grow well without soil, but that they have to plant fruit trees outside of the pool.

They’ve turned their pool from a suburban water-suck into a densely fertile mini-farm. It’s easily replicable and is ideal in arid places such as Arizona because it uses such a small amount of water. People in the neighborhood were curious and began coming by to check out the pool. To spread the word, the McClungs started a MeetUp group. It now has more than a thousand members. They’ve developed a big volunteer network to help build new Garden Pools. Dennis says that about a third of them are installed in actual pools, and that they dig ponds for the rest. With a volunteer team they can build one in about a day. McClung is a perpetual tinkerer, and the Garden Pool has become something of a science experiment. He’s testing soil in the front yard and growing fruit on the roof. In addition to the circular aquaponic system, which he’s continually tweaking, he has designed a UV water sterilizer that’s housed in a five-gallon bucket.

Neighbors interested in the McClungs’ pool come by for a tour

Farming in Mesa’s arid climate has taught them lessons that transfer to other hot, dry climates. Their next move is to take what they’ve learned in the suburbs and bring it to other deserts, food and otherwise. Dennis says the most interesting part now is figuring out ways their system can be used in low-resource areas where farming is the backbone of the economy. He’s going to Ghana next year and trying to figure out the best way to build farms there. “I’m basically turning my front yard into West Africa,” he says. Dennis wants to turn their house and their farm into a research center focused on how they can help build farms in other desert regions and develop local food systems. He says that if they can make it work there, in suburban Arizona, anyone can grow their own food. “In the States it’s cool, it’s kind of like a novelty, but in the Third World I think it can really make a difference,” he says.”

by   /  18 Aug 2014

“When Dennis and Danielle McClung bought a foreclosed home in Mesa, Ariz., in 2009, their new yard featured a broken, empty swimming pool. Instead of spending a small fortune to repair and fill it, Dennis had a far more prescient idea: He built a plastic cap over it and started growing things inside. Thus, with help from family and friends and a ton of internet research, Garden Pool was born. What was once a yawning cement hole was transformed into an incredibly prolific closed-loop ecosystem, growing everything from broccoli and sweet potatoes to sorghum and wheat, with chickens, tilapia, algae, and duckweed all interacting symbiotically to provide enough food to feed a family of five. Within a year, Garden Pool had slashed up to three-quarters of the McClungs’ monthly grocery bill (they still buy things like cooking oil and coffee and, well, one can’t eat tilapia everyday). Within five years, it’d spawned an active community of Garden Pool advocates – and Garden Pools – across the country and the world.

What began as a family experiment and blog is now a 501(c)3 nonprofit with a small staff. Garden Pool has been voted the Best Backyard Farm in Phoenix, gotten press from National Geographic TV and Wired and Make, and formed a Phoenix-area Meetup group that has nearly a thousand members. It’s attracted hundreds of local volunteers, students, and gardeners who’ve helped build a dozen more Garden Pool systems in and around Phoenix. Scientists and engineers from Cornell University, Arizona State University, and even the space industry have all visited Garden Pool. This spring, “GP” volunteers paired up with Naturopaths Without Borders to travel to Haiti and build a Garden Pool there. Plus, Dennis says, “we’ve helped maybe three dozen being built across the country” through email and phone consultations, “from Florida to Toledo to Palm Springs.”

At first, McClung just wanted his own family to live more sustainably. Now that he’s seen the all the traction these ideas are getting, and how awesomely productive a Garden Pool can be, he says, “I want everyone else to build great systems.” And these systems are pretty great. Instead of soil, the Garden Pool’s plants grow on clay pellets or coconut coir. Excess moisture drips into the pond below, and that, plus a rain catchment system, means that the whole thing requires a tiny fraction of the water used in a conventional garden. This is especially crucial in a place like Mesa, which gets just a little over nine inches of rain per year.

Instead of commercial fertilizer, chicken droppings fall through wire mesh strung across the pool’s deep end, nourishing the algae and duckweed in the pond below. The tilapia eat the pond plants, release their own nitrogen-rich excrement, and the fish water then gets funneled (using a solar-powered electric pump) into the hydroponics system that grows the family produce. The McClungs have added pygmy goats and a bunch of fruit and nut trees to the backyard mix, so their mini farm is starting to look a lot like a very hopeful — and very delicious — urban future. Dennis says building your own Garden Pool is not as labor-intensive and complex as it sounds.

In addition to free online tutorials like “Getting Started in Barrelponics” and “Growing Duckweed & Azolla,” McClung teaches GP certification courses; so far, he’s certified about 20 “GP” enthusiasts in Arizona and about 12 more during the trip to Haiti this spring. He plans to help a few recent grads start their own Meetup groups in Los Angeles and New York. He also just released the second edition of Garden Pool’s extensive how-to book, featuring 117 pages of detailed instructions, illustrations, photos, and QR codes that link to video tutorials. His goal is to encourage aspiring Garden Poolers to build and maintain their own aquaponics greenhouses, whether or not they’ve done anything remotely like it before, and whether or not they even have a pool. (One of Garden Pool’s main taglines is “use an old pool or just dig a pond!”)

Thanks to endless experimentation with new crops and filters and catchment systems, McClung claims his backyard is now “basically a Frankenstein laboratory” and not quite as pretty as the sparkling Garden Pool replicas and spinoffs he’s helped build around town. Various experiments have met with varying degrees of success (blueberries and amaranth didn’t do as well as eggplant and asparagus, for instance), but the list of things that grow like weeds in Garden Pool is long (McClung advises you to check out page 96 of his book). He manages pest control by doing things like adding ladybugs for the aphids and selecting plants like marigolds and garlic, which repel whiteflies and spider mites, respectively. Since the system is closed and controlled, it’s a pretty fantastic way to experiment with organic gardening methods.


As far as they’ve come in the past five years, though, Dennis says they’re just rolling up their sleeves. Now that all the nonprofit paperwork is settled, Garden Pool staff can apply for grants, and, he hopes, “hop from place to place and make stuff happen.” He’d like to help build more Garden Pools in Haiti, Africa, South America, and across the globe, and eventually become something of an international hub for closed-loop system research.”


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