How the Water Dept. and civic hackers are helping student gardens go high tech
The smell of manure hangs in the air at Nebinger, a K-8 public school in Bella Vista, as Matthew Fritch kneels in the garden on the playground’s periphery. An environmental engineer at the Philadelphia Water Department (PWD), he jabs red and green sensors that look like cartoonish darts into the ground, then steps away from them and the attached plastic box filled with wires and a circuit board. As he types a web address onto his laptop, he’s careful to avoid using the fingers covered in soil.
For more than a year, Fritch has been developing a soil-monitoring kit with a volunteer group of civic hackers. In a few weeks, the first batch of greenSTEM Network devices will be introduced to four public schools — Nebinger, Greenfield, Cook-Wissahickon and the Science Leadership Academy’s Beeber campus — and he’s doing a few last-minute tests on something he essentially built from scratch.
The kit’s basic function is to measure a garden’s moisture level and send that information to a website so kids in the classroom can determine if their plants need attention. But since students are involved in all stages of this hands-on science project — from soldering circuit boards, to programming the device, to designing and building protective housings, to monitoring the data — greenSTEM Network is also an introduction to subjects like science, technology, engineering and math (i.e., STEM).
Cash-strapped schools won’t have to pay a dime for the kits; the project is entirely funded by a $10,000 grant from the National Oceanic and Atmospheric Administration.
This D.I.Y. science project is part of “Green City, Clean Waters,” the Water Department’s $2.5 billion effort to improve the city’s sewer system and make the rivers fishable and swimmable again.
“The big problem in Philly is that when it rains, our sewage overflows into the rivers and streams,” says Fritch. “The way that we’re dealing with it is in this green, natural way, where we put in rain gardens, a green roof or porous pavement where the water can go down into the ground so that it doesn’t overwhelm our sewers and kill fish.”
Around the city, you might have come across a corner of sidewalk that’s been torn up and replaced with a shallow pit. That’s the start of a rain garden. Plants will eventually grow over the depression, capturing runoff from impervious surfaces, like asphalt and concrete, and ultimately prevent pollutants from entering the sewer system. This type of renovation is less expensive than investing in new “gray” infrastructure — underground storage tanks and pipes — and the sowing of native plants is a bonus.
Over the next 25 years, the Water Department will install green storm-water infrastructure like this in thousands of locations around the city. Schools are receiving special attention, partly because playgrounds can be vast swathes of impenetrable asphalt.
In 2011, Nebinger became the first school to partner with the Water Department for Green City, Clean Waters. With the help of a $400,000 grant from PWD and the Enviromental Protection Agency, the schoolyard underwent a massive renovation. Part of the blacktop was torn up and replaced with a permeable surface; a rain garden was planted around the periphery.
“We thought it would be a good idea to have the kids connect with those rain gardens and have some STEM education attached to this whole program we have going on,” says Fritch.
Inspired by his experience tinkering with Arduino, a computer chip favored by electronics hobbyists, Fritch brought his concept for a soil-monitoring kit to Tech Camp, a hackathon sponsored by the U.S. State Department and the Philadelphia School District. Fritch scribbled his project idea on a whiteboard along with others trying to address problems within the local education system, and was soon approached by programmers Christopher Nies, Jason Blanchard and Kevin Clough. Within eight weeks, they had a prototype, an open-source kit housed in a clunky, flower-shaped casing they called the Solar Sunflower.
Hackathon projects are often forgotten once the weekend passes, but in the months since, a core group of three people have refined the product. They meet every week at DevNuts, a collaborative workspace in Northern Liberties where civic hackers work on public-service projects as part of Code for America, a partnership between local governments and technologists with chapters across the country. When I went there on a Thursday to speak with Nies and Fritch, a dozen people were seated at a long, narrow table, huddled around their glowing laptops in almost absolute silence. The smell of pizza was pungent.
“Originally, we built a giant metal sunflower, but got tired of lugging that around town and we decided that the students should build their own housing for the sensors,” says Fritch.
He points to the red and green probes. “These are the soil sensors that go underground like the roots.” Long black wires connect the sensors to a waterproof case containing a temperature gauge and a microcontroller. This transmits data to a computer in the classroom via radio frequency (eliminating the need for a WiFi connection outside).
Rather than monopolize a precious school computer, the greenSTEM Network uses its own credit-card-sized Linux computer called a Raspberry Pi, which costs only $35. Once the mini-computer receives the data, it loads it onto a website where students can monitor their garden.
“Raspberry Pi is so off-the-shelf cheap, like, anyone can afford it, even in the current school scenario, it’s really not that expensive,” says Nies. “The entire kit costs about $250.”
“A commercial product that does what this does would cost thousands of dollars,” says Fritch. “And it does less than what this does,” adds Nies.
When students go to greenstemnetwork.org, they’ll see the data expressed in the form of a tree, with a cluster of leaves representing each school. The colors change from red to yellow to green depending on the dryness of the soil. (Clough and Ali Wiest — both from Northern Liberties software company Jarvus Innovations — did the visualization.)
“The point is that it’s going to be a map showing how all the schools are in this network and if they click on a leaf which represents a school, they’ll have data about what’s going on at the school,” says Nies.
For a number of weeks, Fritch has been meeting with students at Science Leadership Academy Beeber, teaching them everything from soldering to programming. He’s hoping they’ll be the first large-scale manufacturers of the sensor kits.
“One of the most amazing parts of the project is being able to really involve the students in the learning,” says Nies. “Having kids build circuit boards, I mean, that’s the sort of electronics education you haven’t seen since the ’50s.”
Beyond installing rain gardens at schools, the Water Department, in collaboration with Fairmount Water Works, created an urban watershed curriculum that teachers started using in the classroom last year.
Rachel Odoroff, a seventh and eighth grade science and math teacher at Nebinger, is one of them. “We’ve been doing all kinds of things, from studying the water cycle, to building water wheels, to looking at how water works with civic organizations and the infrastructure of the city,” she says.
She’s taken her students on field trips to the Water Works, a reservoir and, most memorably, a sewage treatment plant on a 96-degree day.
“I’m an environmentalist and I think students need to become aware of the environment and also to understand that their city blocks and neighborhood are part of a larger ecosystem, and water is a really, really critical resource,” says Odoroff.
Last year, she worked with Fritch to introduce her students to an early incarnation of the greenSTEM Network’s soil-testing kit, which the students made to look like a crude reptile. “We put a fake snake in the garden and the eyes lit up when it needed water,” says Odoroff.
This year’s device is more sophisticated and Odoroff has already imagined how she’ll use it to teach. “It creates a daily graph, like you can graph every week how much rain you’re getting, how much water’s in the soil when you have dry periods. That’s, of course, one of our big math standards … looking at graphs,” she says. “It’s good for the kids to chart and make predictions about what’s going on.”
In preparation for their kit’s arrival, some of her students entered a competition to design the housing. Amir Woodson, one of Odoroff’s eighth graders, created Nebinger’s winning sketch, a spider-like housing where the legs are the wires that go into the soil.
When the device was demoed to the class, Woodson remembers being fascinated by it. “It’s like having your own second mind, like having a little helper,” he says.
Last year, Woodson, an aspiring surgeon, attended George Washington, which doesn’t have a garden.
“We just had asphalt so you didn’t do nothing like that,” he says. “When I went to Nebinger we had a garden. At the beginning of the school year we ate the vegetables and throughout the year we would take care of the plants.”
On a practical level, he says the soil kit will teach him when to water the garden and how much. But on a deeper level, “It will teach me how to love plants,” he says.
“The students love anything that’s hands-on,” says Odoroff. “They love getting out into the garden and we’ve done a lot of work with the kids explaining what’s going on. It makes it much more real to them in terms of how things grow, how the environment is affecting the inner-city, and it’s a chance for them to get out of their seats and have some ‘real’ time.”

