Six years ago, Julia Marsh gathered with friends in the kitchen of her small Brooklyn apartment. She’d ordered some flour-like powder derived from seaweed off the internet, and — after watching tutorial videos on YouTube — she needed help with the baking required to turn it into an environmentally-friendly, compostable plastic.
“Early on, it was purely experimental,” said Marsh. “Let’s just see what we can make.”
As she smeared a sweet-smelling goo onto baking sheets, Marsh, then a design student at the School of Visual Arts in New York City, deliberated about what temperature to set the oven. Several trials later, her first bioplastic prototypes were born.
“They were ugly,” she said, and only “kind of resembled” plastic. But these early experiments gave the Monterey Bay native the confidence to fight against the torrent of single-use plastics threatening the oceans she grew up playing beside.
In 2020, Marsh co-founded Sway, a San Leandro startup that aims to replace conventional plastic packaging, made from petroleum products, with a green alternative. This year, Sway and four fashion brands will launch their first fully compostable seaweed-based “polybags” — the clear plastic packaging that protects new garments during delivery.
Conventional polybags are an environmental nightmare, breaking down into microscopic pieces, entering waterways and even our food.
According to the UN Environment Programme, nearly 11 metric tons of plastic enter the oceans each year. These discarded plastics are killing marine animals including turtles, fish and seabirds, who can die from entanglement or from eating plastics.
“A lot of animals are eating our trash,” said Marcus Eriksen, co-founder of the 5 Gyres Institute, a plastic pollution research nonprofit based in Santa Monica.
Marsh sees this pollution as an affront to her upbringing on the Northern California coast. “When we would go down to the beach, my dad would say, ‘Never turn your back on the ocean,’” she said, recalling his safety tips. “But I like it as a metaphor. We need to be turning toward the ocean and paying attention to this great power that makes up the majority of this planet.”
For garment makers trying to be green, finding an alternative to conventional plastics is a priority. Alex Crane — a company making clothing out of renewable materials including fibers from banana trees and coconuts — is one of the four brands in the Sway Innovation Coalition.
“It’s always weird when you see companies preach sustainability and then the product comes in a plastic bag,” said Aaron Smith, the company’s chief operating officer. “It feels like one step forward and two steps back.”
Another early adopter is Florence, the outdoor gear company founded by three-time world surfing champion John John Florence.
“He practically lives in the ocean,” said Bruce Moore, director of innovation and sustainability at Florence. “He sees pollution firsthand and wants to do something about it.”
There are many plastic alternatives on the market, but not all are compostable within a short time. These “green” products live in a gray area, requiring intensive industrial composting to be completely broken down.
Tests run by Cold Creek Compost in Ukiah showed that Sway’s bags were nearly completely broken down after 60 days. The company is now seeking certification that its products can be broken down in a backyard composter together with food scraps and garden waste.
While investigating a material to use to make green plastics, Marsh researched crops like corn and sugarcane, before deciding on an alternative that resonated with her Monterey Bay upbringing.
As the daughters of a florist and a fisherman, Marsh and her sister would, as children, adorn sand mermaids with seaweed hair and use washed-up kelp as jump ropes.
“It was familiar to me. And then it became an obsession,” Marsh said.
In 2018, shortly after the early experiments in her Brooklyn kitchen, that obsession led Marsh and her partner Matthew Mayes, co-founder of Sway, to Indonesia, one of the largest producers of seaweed in the world. After wading out into the turquoise blue waters at a seaweed farm, Marsh was amazed by how quickly the crop grew. “The farmer would give it a haircut and two weeks later it would regenerate,” Marsh said. Unlike conventional crops, this type of aquaculture requires no fresh water, pesticides or arable land. Farmers simply reel out lines embedded with seaweed spores and let the algae flourish.
Farmed seaweed also creates an underwater sanctuary for fish and invertebrates to shelter in and raise their young. And because the seaweed is trimmed rather than being harvested in full, that ecosystem stays in place.
Today, Sway’s seaweed comes from farms in Asia, North and South America, East Africa and Europe. So far, Sway has only sourced from Maine and Alaska in the United States. Marsh wishes she could incorporate local seaweed into her products, but there are no commercial seaweed farms in California.
Catherine O’Hare, the company’s seaweed sourcing specialist, is working on a scorecard to ensure that suppliers meet Sway’s ethical standards. She will evaluate the social and environmental impacts of each new partner, such as their ability to provide fair wages and track ecosystem health.
The launch of Sway’s compostable garment bags is a start, but with the fashion industry still using billions of conventional polybags each year, Marsh is well aware of the magnitude of the challenge that lies ahead.
“Plastic production is only increasing. It’s not going down yet,” she said. “I’d rather know that this work is pointing us in the right direction. I firmly believe in a future where seaweed will become a mainstream part of people’s daily lives.”
