Feeding Future Megacities With Floating Hydroponic Farms

A team of engineers has designed a hydroponic module that could shift urban farming from the rooftop to the sea.

By 2015, it’s estimated that 340 million people will live in 21 global megacities. As these urban hubs swell, there will be a race to transform the infrastructure that feeds and supports them. To do that, we’ll need new system of growing produce with this challenge in mind. There aren’t enough fields to do that. But there are enough oceans.


To that end, former students at the Royal College of Art and the Imperial College, London, Roshan Sirohia, Jason Cheah, Sebastiaan Wolzak, and Idrees Rasouli, have created SeaLeaf, a modular hydroponic unit that can grow vegetables while floating like a buoy. The team has demonstrated in at least one test that it can grow seven to eight yields of bok choy a year, while conventional farming only produces two or three. Because 18 of today’s megacities currently sit on coastlines, the team envisions a network of climate-resilient SeaLeaf farms that can feed millions of people. In theory, the farms would only be as far as a kilometer from the nearest pier.

SeaLeaf runs on solar cells and is made of recycled high-density polyethylene (HDPE), but was inspired by traditional means of farming on water in Bangladesh. There, farmers have been constructing floating farms on beds of bamboo and water hyacinth to accommodate floods for hundreds of years. But because SeaLeaf controls for the amount of sunlight plants are exposed to through its “smart lid,” the tool could be used in a number of locations, even under harsh exposure to the sun.

Similar to Bangladesh’s rows of sturdy plant beds, farmers would collect SeaLeaf’s produce trays through a series of specially designed walkways.

“The idea is that the entire farm sits along the coast, within a kilometer or two kilometer radius. You’d reach the farm via your existing infrastructure used for fishing–either boats, or small sized ships–and then once you get on the farm, you launch yourself onto the walkways,” Sirohia explains. “In the future we’d like to explore faster ways of accessing the produce, because harvesting individual trays could be time-consuming,” he adds.

Sirohia, Cheah, Wolzak, and Rasouli won a Core77 design award last month for their work, but now that all four have graduated, they’re looking to find both funding and a site to test a full SeaLeaf farm. Singapore, which imports 93% of its food, is one option, and the team is preparing to speak to the local government to launch a pilot. There are also several design aspects that still need to be worked out–for example, a reverse-osmosis system that can convert seawater into nutrient solution in case the plants don’t get enough rainwater, as well as a way to better balance the modules.

Most importantly, the designers have yet to test the concept as a network of floating modules, and to see how those units impact existing sea life on a larger scale. “We’re looking to start the second duration of the project and take all these elements that were tested and get users to use it,” Wolzak says.


“We’re working on the size, working on the form, as well as working with fish farmers to bring in their feedback into the Sealeaf,” Rasouli adds. “After that, we’re looking for funding and opportunities to create a much more developed version.”

About the author

Sydney Brownstone is a Seattle-based former staff writer at Co.Exist. She lives in a Brooklyn apartment with windows that don’t quite open, and covers environment, health, and data.