When you ask Brandon Hebor and Steven Bourne what they do for a living, don't expect an average answer.

They grow food with fish poop.

The pair co-founded Ripple Farms, an agri-tech startup, in 2016 after graduating from Seneca College's green business management program.

"Both of us were looking at something that we could apply our knowledge or expertise into to help make the world a better place," Hebor, the company's chief operating officer, said.

The way they decided to do that was tackling the issue of food insecurity.

"Bring the farm to the city to reconnect people with food," Hebor said. "That was our starting point at Ripple Farms: how can we bring the farm to the city and engage people with agriculture in a way that they've never interacted before?"

Brandon Hebor and Steven Bourne co-founded Ripple Farms, an agri-tech startup, in 2016 as a way to tackle food insecurity in Toronto. 2:41

'Undying passion for agriculture'

Bourne, the company's chief executive officer, says he had Ripple Farms in the back of his mind for a while, but it wasn't until he met Hebor that the pieces of the business puzzle started to fall into place.

Hebor is the science part of the duo. He graduated from McMaster University with a degree in environmental science and has been a hobby farmer ever since he planted his first seed at eight years old in his grandparents' garden in Etobicoke.

"But how do you grow up in the city of Toronto and think that you may even be a farmer?" Hebor said. "It's just this concrete jungle — or an asphalt farm, in the nicest sense — but I had this sort of undying passion for agriculture."

Bourne, on the other hand, has a brain for business. He was 10 years old when he first started making money by shoveling driveways, and went on to get a bachelor of business administration at Trent University in Peterborough.

Leafy greens are Ripple Farms' specialty, including kale, lettuce, swiss chard and mint. (Petar Valkov/CBC)

It only took one meeting in the summer of 2016 to plant the Ripple Farms seed. Hebor and Bourne took their idea to Secena's on-campus incubator, HELIX, to get some business coaching, and it took off from there.

​"We were two guys with a piece of paper and a dream," Hebor said.

They focused their business plan on the idea of using aquaponics to grow food in urban areas. The practice is a combination of aquaculture — raising fish — and hydroponics, which uses water instead of soil to grow plants. The men decided they would use a shipping container with a greenhouse on top for their operations.

Forty-five tilapia swim in this 150-gallon tank, located in the bottom floor of the shipping container. (Petar Valkov/CBC)

They started small, pouring their own money into a preliminary pilot project that secured them several partnerships. Then they inked a deal to set up the pilot at Toronto's Evergreen Brick Works in November 2016.

By the following January, they had food growing on site.

The pair used the 160-square-foot vertical farm at Evergreen as a research project, capturing data and understanding how a small-scale operation works. They custom designed the system inside, first growing 365 plants, then scaling up to nearly 600.

The 160-square-foot vertical farm sits on Seneca College's Newnham campus. (Petar Valkov/CBC)

When temperatures hit -27 C during their first winter in the steel shipping container, the greenhouse remained at a relatively balmy 14 C.

Bourne said they learned a lot using a from-the-ground-up approach. By starting small and allowing operations and technologies to progress as they went, they felt ready for the next step: a second farm on Seneca College's Newnham Campus.

How it works

The aquatic ecosystem is in the bottom of the shipping container. Forty-five tilapia swim in one 150-gallon tank, while a second tank holds 80 fish.

Hebor explains the science behind Ripple Farms. (Petar Valkov/CBC)

Hanging above the 150-gallon tank is a shelf containing seedlings planted into a small amount of soil. Warm, moist air rises up from the fish tank, going into the root system of plants like kale, lettuce, Swiss chard and mint.

They use tilapia not only because the fish are hardy, but because they are a tropical fish. Warmer water evaporating from the tanks means warmer moisture for the plants' roots, making them grow faster.

As well, all of their operations are certified by Ocean Wise, which means they are a sustainable seafood option.

The entrepreneurs use tilapia because they are resistant to changes in water chemistry. (Petar Valkov/CBC)

A perforated pipe draws water from the centre of both fish tanks, cleaning out sediment, uneaten fish food and fish poop. It then travels to a radial filter that brings sediment to the bottom to ensure it doesn't clog the rest of the system.

Finally, the water travels to a bioreactor, where the naturally-occurring nitrobacteria converts toxic fish poop into healthy plant food.

It takes about three weeks for a seed's roots to penetrate the soil. When that happens, it's time for the seedling to move upstairs to the greenhouse where it will spend another month or so before it's ready to be harvested.

Biomedia helps transform toxic fish poop into healthy plant food. (Petar Valkov/CBC)

Ripple Farms uses what's called a Deep Water Culture system, which means the seedlings sit in holes in Styrofoam instead of being planted into soil. The water is constantly flowing through the system from downstairs, meaning the water is full of nutrients and is also being aerated in the process.

Right now, the food produced at the farm on Seneca's campus is harvested every week and goes directly into the cafeteria's smoothie and salad bars. The goal is to develop Ripple Farms into a large-scale operation.

"It's always been our dream, to get to that large scale — feeding as many people as we can," Bourne said.

Plants sit in a kind of Styrafoam raft in water rather than being planted into the soil. (Petar Valkov/CBC)

'A workforce in the future'

Bourne and Hebor say one of their favourite parts of owning the business is the engagement piece. They do educational workshops for children and adults alike to teach them about aquaponics, agriculture, and why Ripple Farms matters.

"If we go into a presentation and Steve and I say, 'We're farmers of the future,' people are like, 'Well, what does a farmer of the future look like?'" Hebor said.

"At the end of the day, we're trying to inspire people to get into agriculture," Bourne added. "The younger generations are so passionate about it. I always say it selfishly, but we need a workforce in the future."

"If we can inspire just one per cent of this population to get into this, that's a win in our books."

Start-Up City is CBC Toronto's five-part digital video series that spotlights some of the GTA's most innovative start-ups.