Michelle Zaludek/Mustang News

Zion is hidden behind a dense thicket of trees and thistles. It’s a place where small fish and prawns poke around freshwater ponds; where plantlife stretches, basking in the humid air.

Student caretakers make the hike to Zion at least once a week to tend to it — to make sure the fish have enough to eat, the water levels are high enough, the pumps are still moving and the covering on the greenhouse is still intact.

Zion is a synonym for Jerusalem. And it’s a national park. It was even the last human city in sci-fi classic “The Matrix.” And at Cal Poly, it’s a greenhouse in a little corner of the Cal Poly Student Experimental Farm. So if the name sounds ambitious, it’s because they have big goals.

“We’re trying to push the boundaries of what’s acceptable to grow with aquaponics,” civil engineering senior Dylan Robertson said. “We’re growing potatoes and sweet potatoes and onions — we’re growing root crops in nothing but water. We’re growing bananas and raspberries and blueberries and horseradish and ginger and garlic … We’re growing a cypress! A giant hardwood tree. We’re even growing hardwood bushes like rosemary, all in water.”


Aquaponics is a water farming system that pumps water through a series of freshwater ponds, tanks and rock beds. Fish, crayfish and other life provide nitrogen-rich fertilizer to the water. That fertilizer is soaked up by plant life, thereby cleaning the water for the fish back at the beginning of the system.

Among other things, the system also grows milkweed, kale, lettuce and “the most delicious tomatoes you’ll ever have,” according to mechanical engineering senior Erik Pinuelas.

The setup inside is a system of six pools, tanks and rock beds that push water in a giant circle with the intention of creating a symbiotic, nearly self-sustaining relationship between freshwater creatures and farmable plants.

The science, called aquaponics, is currently tended to by the PolyPonics club. They’ve mostly been experimenting with just what can be grown with a water-based farming system. And Robertson said they’ve been able to grow a lot.

Club members get to take home the food, which they said doesn’t currently produce enough for them to be able to sell.

Trouble in paradise

But they’re always facing the looming threat of losing Zion.

“We’re at the Student Experimental Farm, which is a very temperamental place,” said Robertson, one of the founding members of PolyPonics. “And we’re constantly worried someone’s going to pull the rug out from underneath us.”

The club is responsible for maintaining the greenhouse, and said they only receive funding through grants and the Associated Students, Inc. (ASI)’s annual $500 stipend for clubs.

“I want, like, $10 million,” Robertson said. “No, it’s just — right now we get almost zero support … I wish Cal Poly saw the value in it like we see the value in it.”

It doesn’t help that PolyPonics has recently faced serious setbacks that drained what funds they had.

The plastic skin covering the greenhouse broke a few months ago. And around the same time, the greenhouse’s only power source short-circuited, causing the water pump to stop. Larger fish that the club could have harvested, such as tilapia, living in the ponds couldn’t get oxygen when the water stopped flowing and died, according to forestry and natural resources junior Jase Tweedy, the club’s president.

PolyPonics was responsible for fixing all of it.

“If we don’t fix it, it looks like trash up there, and Cal Poly could shut us down because it looks like a dangerous mess,” Robertson said.

Robertson said PolyPonics had to raise $1,200 just to fix the greenhouse skin: “So yeah, $10 million would do the trick.”

With extra funding, PolyPonics could start collecting data on the system that could be used to explore an agricultural technique that they think is just as innovative as it is simple.

“It’s basically growing crops off fish poop,” environmental engineering senior Erik Hoffnagle said.

Robertson expanded: “It’s a symbiotic relationship between many different organisms that creates an excess that we’re able to harvest and use for ourselves.”

And amid California’s historic drought, the aquaponics system uses significantly less water, according to Tweedy.

Because PolyPonics doesn’t have to water an entire field, it loses less water to evaporation. Tweedy suggested that on their scale, the water savings could be as high as 80 percent.

But Robertson said there hasn’t been enough formal research to prove that.

“It does use way less water than soil farming,” Robertson. “And as California’s drought gets worse and worse and worse, we have the answer already. You know, drip irrigation is cool, but aquaponics and hydroponics will be even cooler.”

The lack of university-level research leaves a lot of room for Cal Poly to step in and be at the forefront. Tweedy said that in the immediate future, he’d like to see more students using the aquaponics system as a springboard for senior projects. And he’d eventually like to see the system incorporated into Cal Poly’s curriculum.

“I know there’s an aquaculture class,” he said. “But it would be cool to see this turn into a lab class or something like that.”

Pinuelas said the need to explore aquaponics is growing as the world continues to develop, and that the time to seriously research it is now.

“There’s almost an infinite amount of benefits to aquaponics,” he said. “And where it meets us in the present is that, within agriculture, we’ve hit this growth-rate cap. Because we’re limited on farmland … And society’s going to GMO, but aquaponics is an alternative solution, because it doesn’t require arable land. It requires a vacant lot, your backyard, your kitchen counter, all the space that’s already available.”

With a system that a massive variety of plants, fish, crawfish, shrimp and even a recently rescued turtle named Chance all depend on to survive, there’s a lot at stake for the PolyPonics team. But with any luck, the team will be able to keep pushing to make sure Zion doesn’t become a paradise lost.

Leave a comment

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