Jay Barnes needed to switch gardening techniques or his family’s farm in Lamoine would never grow anything again. His farmland had been in continuous production for over a hundred years, but when his father switched to chemical fertilizer, the soil’s ecology quickly collapsed.
“There wasn’t any earthworms or anything,” Barnes said.
Barnes and his family switched to organic gardening. They used crop rotation, composting, cover crops and an age-old remedy: seaweed.
“All the earthworms came back,” Barnes said.
Barnes is now a big believer in seaweed. Every year, he takes several trips to Lamoine Beach to fill the back of his pickup truck with kelp and rockweed. He estimates he mixes between four to six cubic yards of seaweed into his compost a year.
Seaweed is not a new gardening trick; coastal farmers around the world have used it for centuries. But its popularity in the United States has grown in concert with the expanding organic farming and gardening movement. Organic farmers are constantly on the lookout for natural materials that can replace chemical fertilizers while performing just as well, and seaweed seems to fit the bill.
In recent years, lawn and garden companies have begun to tap into seaweed’s potential, as well.
George Seaver is research coordinator at Ocean Organics, a Waldoboro company that specializes in seaweed products for golf courses. He says seaweed’s unique attributes make it a perfect fertilizer. It’s rich in beneficial trace minerals and has hormones that stimulate plant growth. It also has less cellulose than land plants, making it easier to grind up. And because seaweed is an aquatic plant, it shares no diseases with land plants.
Seaver’s company dries and granulates seaweed into an extremely fine meal. “So [it] can disappear even into a golf course,” he said.
Ocean Organics also has formulated a seaweed solution to spray onto golf turf. By using seaweed, course landscapers can reduce their traditionally high need for chemical fertilizers.
“It makes liquid fertilizers very, very efficient,” he said.
Seaver first became intrigued by seaweed after taking a job at Atlantic Labs, a Maine company that makes seaweed-based fertilizer for farmers.
“I got more and more interested in this magic product it seems to have,” Seaver said.
He became a believer after watching the effects of a pint of liquefied seaweed sprayed on an acre of potatoes. The potatoes soon grew visibly bigger.
“It got me glued to the subject,” he said.
Another company, Coast of Maine Organic Products, has been selling a seaweed-based mulch for years. At first, the product didn’t sell well. Peter Bottomley, director of sales and marketing at Coast of Maine, says they then changed the product name from “Kelp and Humus” to “Enriching Mulch with Seaweed.”
“And [now] it’s selling like crazy,” Bottomley reports.
Coast of Maine gets its seaweed from a Nova Scotia company that cultivates it.
“The guys who are doing this are growing it in vats,” Bottomley said.
The Nova Scotian company extracts carrageenan from seaweed for use as a thickener in ice cream and other foods. Coast of Maine then takes what’s left and combines it with aged bark to make a nutritious gardening mulch.
If cultivated seaweed becomes a trend, that might be good news for the ocean, says Dr. Eric Sideman, director of technical services for the Organic Farmers and Gardeners Association. Still, Sideman is reluctant to endorse seaweed for use in organic gardening because of the damaging effects of overharvesting.
“I don’t think anyone should be harvesting any living seaweed,” Sideman said. “It’s like harvesting a forest.”
Sideman says harvesting seaweed from the ocean can play havoc on the sea’s ecosystem. Any area cleared of seaweed will remain clear for a long time and seaweed zygotes have a tough time reestablishing themselves. Sideman says taking already-cut seaweed that has washed up on shore would be an ecologically-friendlier choice.
For gardeners that want to use shore seaweed, there are several options. The first is to grind the seaweed into a mulch and spread it onto the soil. Another option is to soak seaweed in water and then spray the garden with the resulting tea.
Ocean Organic’s George Seaver says that no matter what method a farmer or gardener might choose, seaweed is always going to be beneficial. “If you just drag seaweed off the beach and throw it onto the garden, you’ll help your garden,” he said.