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With More Varieties and Growing Demand, Seaweed is Maine’s Crop to Watch


With more varieties and growing demand, seaweed is Maine’s crop to watch

Photo: Derek Davis/Staff Photographer

CLARK COVE, WALPOLE — One farmer wore waders, the other was holding hundreds of 5-week-old seedlings in one hand. Their “tractor” was afloat. It was November and planting season at Maine Fresh Sea Farms was in full swing, in spite of a dungeon of fog that made the farm, a football-field-sized area of the Damariscotta River estuary, hard to see.

Seth Barker drove the boat while Sarah Redmond did the planting, which in the case of seaweed farming looks akin to casting on in knitting. That is, if instead of needles one used a thick hank of marine rope strung horizontally between moorings and substituted a 200-foot-long spool of twine covered with tiny bits of seaweed for a skein of yarn. As Barker chugged slowly through the water, Redmond played the twine out, twisting it around the marine rope.

Planting was over in less than 10 minutes, and the new crop, alaria escultenta, or “winged kelp,” was ready to flourish in the cold water. Next to it were ropes of sugar kelp and dulse in various stages of development.

The methods are not brand new, but three things made this crop of special interest. The seedlings had been certified organic by MOFGA, the Maine Organic Farmers and Gardeners Association. They were of an edible variety still in the experimental stages of cultivation. Maine Fresh Sea Farms, which is funded by grants from NOAA (the National Oceanic and Atmospheric Administration) and the USDA, is trying to extend growing seasons to harvest crops year-round, or at least nine months of the year. Winged kelp, like most seaweeds, is a winter crop, gathering nutrients from cool ocean waters when the micro algae of spring and summer have cleared out and the light can reach them. As every ambitious farmer knows, being able to deliver crops consistently throughout the year is a key component of building a business, and Maine Fresh Sea Farms wants to sell not just the more traditionally packaged dry seaweed, but fresh.

Redmond, who collaborates with Maine Fresh Sea Farms but works as an extension agent with Maine Sea Grant, began dreaming of being a seaweed farmer at age 15, shortly after the Maine Seaweed Council was formed. Now based at the University of Maine’s Center for Cooperative Aquaculture Research, Redmond is well aware that there are big questions about how well seaweed can be mainstreamed. (Just last month, The New Yorker published an article about seaweed cultivation headlined “A New Leaf,” with the subhead “Seaweed could be a miracle food – if we can figure out how to make it taste good.”)

Still, Redmond is seriously optimistic. She leaned backed on the gunwale and began listing off the crops Maine is famous for, potatoes and blueberries being the most obvious. Then she made a promise.

“We’re going to be known for kelp pretty soon,” she said.


Mainers have been harvesting both red and brown seaweeds – the latter the kind that tend to make small children squeamish about going in the water – for more than a century. Ten Maine seaweeds are harvested or cultivated commercially. All are edible and nutritious, although some more than others have been favored as food. These seaweeds, or “sea greens” as the branding experts would them known, have been used for everything from fertilizing gardens to animal feed to perhaps most consistently, in a financial sense, as a thickening agent for foods like puddings and ice creams. Irish moss, a red algae that yields carrageenan when processed, was driving the economy in Rockland back in the post-World War II years. (It remains an important part of Rockland’s economy, but the company that processes it uses imported seaweeds now.)

That’s the wild stuff. Seaweed has also been successfully cultivated, or farmed, worldwide for years; in 2013, after years of research, the Portland-based company Ocean Approved released a manual on how to grow kelp from spores. Redmond helped develop that manual, which is oriented toward New England waters.

Maine Fresh Sea Farms uses that manual, but they’re already going beyond it.

Those alaria seedlings Barker and Redmond planted were organically produced in the nursery – Redmond grew them naturally in filtered sea water in a tank at her lab in Franklin, but without feeding them the typical synthetic nutrients. (Barker uses fertilizers like fish emulsions for what he has been growing at the Darling Marine Center and because Maine Fresh Sea Farms is not certified organic yet, the final crop won’t be organic.) Kate Newkirk, the assistant director for processing and handling for MOFGA’s organic certification process, laughs when she’s asked if it was a challenge to determine how to determine what organic seaweed farming constitutes. She had to get up to speed on a whole new kind of farm. “Oh yeah,” she said. “It took a lot.”

Ultimately, the criteria focus on the ecosystem. An organic seaweed farmer shouldn’t disrupt natural beds or overtax the ecosystem, Newkirk said. Nor can they farm near fish farms because antibiotics are often fed to those fish. Any processing must be contaminant free. But perhaps the most important component of organic certification is what farmers do to protect the natural resource.

There’s a frontier feeling to this whole enterprise. Seaweed management is itself new; Maine’s Department of Marine Resources is in the process of developing its first plan, focused on management of rockweed, which is not generally eaten but represents more than 95 percent of seaweed landings in Maine.

Simply put, no one wants to deplete seaweeds. These plants protect shorelines, house and feed wild species and are being shown to improve human health. They can even perform what Peter Arnold, one of the founders of Maine Fresh Sea Farms, calls “environmental services.” In one study, seaweed planted right outside a sewage outfall not only thrived, but tested fit for animal feed.

“The indication is the plants don’t pick up the nasty stuff,” Arnold said. “They pick up the nutrients.”