Is seaweed the next kale?
THE HUSTLE - On the shores of the Pacific Ocean just a couple of miles from the village of Cayucos, California, the heat beat down as visitors wandered through a beach coated in shimmering blankets of seaweed, from bull kelp to sea cabbage.
The shores looked like they were in need of a serious clean-up. But the group was actually there for a harvest, led by Spencer Marley of Marley Family Seaweeds. His goal: get people to eat more seaweed.
"All the seaweed we have here in California is edible," he said as he plucked red Nori algae off the rocks.
Yet edible seaweed, which is commonly red or brown algae and includes a variety of subsets, such as kelp, hasn’t quite caught on in the US.
Even with more stores stocking seaweed snacks and salads, the vast majority of seaweed is produced in Asia and imported overseas. US companies produce a mere ~.01% of the world’s seaweed, according to the Food and Agriculture Organization of the United Nations, trailing smaller countries like North Korea and the Philippines by a wide margin.
But American startups are racing to catch up, expanding beyond traditional seaweed products into everything from supplements to seaweed-based livestock feed that studies show could reduce methane emissions from cows.
Will seaweed become a dominant new ingredient, or be permanently relegated to side dish status?
Farming under the waves
On the other side of the country, on a chilly November morning off the coast of Maine, a new kind of farmer tends to their crop. There are no tractors here, no fertilizer spreaders or irrigation systems. Instead, buoys bob on the surface while, seven feet below, long lines of kelp stretch through the frigid Atlantic waters.
This could be the future of farming, according to Kiera Foti, brand manager at Atlantic Sea Farms, which harvested 1.3m pounds of seaweed last year, the majority of the US seaweed crop. Its parent company, Ocean Approved, launched this consumer brand in 2019 and is leading a quiet, underwater revolution in American agriculture.
"[Kelp is] a zero-input crop," Foti says. "It grows very efficiently, just by absorbing everything it needs from the ocean. It's experiencing photosynthesis, utilizing carbon — we have excess carbon in our waters from climate change — and absorbing nitrogen as it grows."
The math is compelling: In just six months, a tiny kelp sprout transforms into a 12-foot-long blade, requiring no fertilizer, no freshwater, and no land.
The kelp, which is high in iodine, calcium, and magnesium is made into products like:
Sea-Chi (a kimchi-inspired fermented kelp)
Frozen kelp cubes for smoothies
Seaweed salad kits
Pureed kelp for sauces, soups, and baked goods
Beyond Atlantic Sea Farms is part of a growing business landscape.
The seaweed industry is projected to reach $85B globally in 2028, and has expanded into unexpected territories – companies are using seaweed extracts in everything from plant-based meat alternatives to natural skincare products, while others process kelp into sustainable packaging materials.
Their high vitamin C, B12, and omega-3 fatty acid content makes these sea vegetables particularly attractive to health-conscious consumers, while their natural glutamates provide the sought-after umami flavor that's become popular in American kitchens.
“Consumers are increasingly looking for snacks that tick all the boxes: healthy, sustainable and now allergen-free,” says Micaela Schuffman, strategic communications expert at Jack Link's, a global meat snack company.
“It’s not just a passing trend; it’s a shift in how people think about food. Snacks like seaweed and kale chips are naturally healthy and eco-friendly, but what’s really adding to their appeal is how they can often be free of common allergens, making them an easy choice for more people.”
Expanding on that demand, Atlantic Sea Farms is already working with partners in the beauty industry, nutraceuticals, and agriculture industries. The company's goal is to expand from 40 to 100 small-scale partner farmers in the coming years.
It's a vision of agricultural growth that doesn't require clearing forests or draining aquifers — just some rope, some kelp sprouts, and a patch of open ocean. And seaweed farming, if the products continue to grow in popularity, may even provide a safer economic option for fishing families looking to diversify their income as climate change threatens traditional catches.
The Gulf of Maine, where most of Atlantic Sea Farms’ operations are based, is warming faster than 99% of the world's oceans, putting pressure on the region's vital lobster industry.
“[Seaweed farming] is really a way to have that more reliable income from a winter season of growing kelp before your lobstering season starts again in the spring," Foti says.
But despite the promise of seaweed farming, scaling up isn't simple.
Growing kelp pains
As simple as actually sea-farming may be, farmers say the regulatory process for leasing ocean space is complex and time-consuming, varying state by state.
Aspiring farmers have to navigate around numerous hurdles, including:
Environmental reviews
Vessel traffic studies
Overlapping jurisdictions between state and federal agencies
This makes even small-scale operations financially daunting to launch. Though state agencies are working to streamline the process, those in the industry say the barriers have stymied progress.
To beat the regulations, some entrepreneurs are finding other ways to tap into seaweed's potential. Take Spencer Marley of Marley Family Seaweeds in central California. A former commercial fisherman and mariner, Marley pioneered a different approach to the seaweed market: experiential tourism.
Marley's journey into seaweed began in 2017 when he sought a way to stay connected to the ocean while raising three kids as a single father. Starting with a simple permit from the State Department of Fish and Wildlife, he began harvesting wild kelp and selling it at farmers markets before branching into foraging tours.
"There's delicious, non-toxic, easy to obtain sea vegetables literally at their feet," says Marley, who has guided nearly 1,300 people on seaweed foraging tours along California's central coast.
The timing proved serendipitous. When the pandemic hit and people were desperate for outdoor activities, his tours exploded in popularity. It's a model that's potentially more viable than traditional farming in California, where complex regulations and coastal politics make large kelp farms challenging.
"In Maine, people love working waterfronts. They're like, 'Oh, the lobster boats!' It's part of the fabric of who they are," Marley says. "In California, it's more like, 'Don't obstruct my view.' If you land on my beach near my property... it's that multi-millionaire mentality of 'I bought it, I deserve it, it's here for me.'"
This tourism-based approach, however, might give Americans a closer view of seaweed's potential. When Marley was selling dried kelp at farmers markets for premium prices, he found that most Americans simply didn't know what to do with it.
"In Western cultures, seaweed will never be the main dish," he says. "The main dish always has to be some protein or something familiar. That’s something that’s hard to change.”
Lab to farm
The biggest uses for seaweed may not involve humans at all. New companies have emerged to explore everything from wild-harvested seaweed for pet food to, more importantly, specialized red seaweed varieties that, when fed to cattle in small amounts, can reduce methane emissions.
Researchers at University of California, Davis discovered that when a specific type of seaweed is added to cattle feed – just 60 to 80 grams mixed into 25 kilograms of regular feed – methane emissions from cow burps drop by more than 80%. In similar trials conducted in Australia, researchers saw reductions of up to 98%.
"In that first experiment, the emissions were reduced by up to 67 percent. I thought at first the equipment must have malfunctioned, but it was real," says Ermias Kebreab, associate dean at UC Davis's College of Agricultural and Environmental Sciences, who was among those leading the study.
While the agricultural sector only accounts for 10% of greenhouse gas emissions, roughly 70% of agricultural methane comes from enteric fermentation, which is done in the stomachs of cows and other grazing animals. Group via Getty Images)
But getting from laboratory breakthrough to farmyard reality isn't simple. Kebreab and his team had to answer some crucial questions: Would the microbes in cow stomachs eventually adapt and start producing methane again? Would the seaweed remain effective after long-term storage? And perhaps most importantly for dairy farmers and ranchers — would it affect milk production or meat quality?
The results were promising across the board:
In a five-month trial, seaweed that had been harvested three years prior still reduced emissions by over 80%.
The addition of seaweed improved beef cattle growth rates with no adverse health effects.
A panel of 112 taste-testers couldn't detect any difference in steaks from seaweed-fed cattle, and nutritional analysis showed no changes in meat quality.
"It's a win for the environment; it's a win for the farmers and consumers," Kebreab says.
The challenge now isn't proving the concept — it's producing enough seaweed to make a difference. The specific variety needed, an algae called Asparagopsis taxiformis, isn't as easy to farm as kelp.
Blue Ocean Barns, a seaweed cultivation company in Hawaii, has developed a land-based nursery system for the algae, using controlled environment tanks that allow them to carefully manage its life cycle stages. It estimates being able to produce enough of the seaweed to feed all US cattle by 2030.
In an era where environmental solutions often require massive sacrifices, seaweed supplements could offer something rare: a win-win scenario for both agriculture and the environment. The question is whether it can scale up production fast enough to make a difference.
