A day after talking to farmer, gardener, and SBS owner Liz Packer of Vineyard Haven about gardening with seaweed and other sea-related products, she calls from the north shore and leaves this message: “I’m standing on the beach and I just have to say that we live in an extraordinary place – most of our waters are healthy enough to still be rife with fish, shellfish, and seaweed.” She takes a breath and continues, “And there is an interconnectedness between the land and sea here that is amazing. I mean, farmers and gardeners in Iowa are not mulching with seaweed or composting sea shells.”
“Fish guts, clam, oyster, scallop shells, lobster carcasses, seaweed, eelgrass – they are invaluable,” says Chris Fischer of Beetlebung Farm in Chilmark. His farm manager, Jason Nichols, runs his hand through some soil in one of the farm’s fields and says, “Look at this. See how rich the soil is?” Chris chimes in, “This has eelgrass, fish guts, and every kind of shell you can imagine.” Jason adds, “And obviously great soil means great vegetables.”
Master gardener Paul Jackson of Edgartown agrees. “The ocean is a great source for nutrients.” He continues, “I used to use eelgrass all the time. I’d pile it up in the early fall, let it break down, and then till it into the dirt, which made for this rich, moist, aerated soil. But the pond [Sengekontacket] is dying and so eelgrass is too hard for me to get now. These days I just use the guts from scallop shells that a few commercial fisherman are willing to drop here.” Indeed, Paul has a mountain of scallop shells next to one of his gardening plots and more crushed shells on his driveway (he likes the dust that gets kicked up from driving over them to float into his front yard plot). He places a ring of scallop shells around all of his fruit trees: “Every time it rains, the rotting guts in the shells feed the trees. You should see the amount of fruit I get!” And each spring Paul makes his own fish emulsion with the scallop shells. He fills a barrel up with scallop shells and their rotting guts and then pours water over them and lets it sit for a few days. “It does not smell good around here, but people who want anything from my garden don’t complain.” He then nourishes all of his transplanted seedlings with the “fish tea.” He says, “You should see the way the plants respond. They love it!”
The Encyclopedia of Organic Farming supports this experience: “You’ll want to use every bit of fish you can get your hands on....It contains all the nutrient elements in abundance. Also, it is a fine bacteria stimulator, thus speeding up the breakdown of other organic matter into humus and improving soil structure....Fish scales, by the way, are the most valuable part, fertilizer-wise.”
Lobster carcasses and shells add calcium and chitins to the soil. Agricultural fertilizer manufacturers use these same chitins to make chitosan, which is a growth stimulator and helps plants be more resistant to fungi. And fish bring all the nutrients of the sea: nitrogen, phosphorous, potassium, calcium, sulfur, magnesium, sodium, iron, manganese, copper, zinc, boron, molybdenum, aluminum, and key amino acids like leucine and glycine. “We had incredible corn,” Clarissa Allen of Chilmark’s Allen Farm remembers. “My dad used to mix fish guts into the soil under our corn – and maybe beneath some of the squash – but we stopped using it when skunks and raccoons came to the Island in the seventies.” (The farm does use fish emulsion in its compost tea.)
Vermin are one downside of using fish guts or shells. Paul admits, “I’ve caught forty skunks and eight to twelve raccoons this year.” Chris and Jason bury their fish guts and shells deep into the Beetlebung Farm compost piles and place fish guts two feet under their tomato plants to avoid attracting skunks and raccoons. “Any guts on the ground, and the raccoons and skunks will decimate whatever you’ve planted,” says Jason.
Of course, having a mountain of scallop shells delivered to your house or getting barrels of fish guts and lobster shells from the fish market might seem a bit hard-core for the average gardener or farmer. “Digging whatever shells and fish remains from your meals into your compost pile will add up over time,” says Lynn Weber, head gardener of Island Cohousing’s prolific gardens in West Tisbury. But if attracting more skunks and raccoons to your neighborhood still feels like a stinky idea, use seaweed. As Liz Packer points out, “Seaweed is just as effective.” Lynn agrees: “It is as powerful as manure.”
According to Rodale’s The Complete Book of Composting, Lynn’s statement is accurate – pound for pound you get about the same nutritional punch. “Fresh seaweed,” the book states, “is rather similar in its organic matter content as compared with ordinary farm-yard manure....Wherever it can be collected easily, with not too much load and expense, it is one of the most ideal materials for fertilizing and composting.” The only thing that is missing is phosphorous, a key agent in helping plants store and transfer energy.
Lynn notes, “People worry about the salt, but there is no need. I’ve never had a problem with it.” Liz adds, “Seaweed is the salt of the earth – every plant and animal needs it. Farmers and gardeners have used seaweed forever.”
The agricultural use of seaweed dates back to at least 1681, according to Rodale, and W.A. Stephenson, one of the first manufacturers of fish emulsion, notes one classic European agricultural practice in his book Seaweed in Agriculture and Horticulture. He describes how farmers in England, France, and on Ireland’s Aran Islands created “lazy beds” – a mixture of seaweed and sand laid on piles of rocks – to create “dirt” for their potatoes. Stephenson writes, “Without seaweed none [potatoes or people] could survive.” Here on Martha’s Vineyard, about one hundred years ago, when Clarissa Allen’s family sold land around Squibnocket, she says, “All they cared about were maintaining the rights to the area’s seaweed. The seaweed – and its fertilizing potential – was all that they thought was valuable about the land.”
Lynn Weber’s practices support the value in seaweed. “We collect it whenever there are drifts of it on the beach – usually after a big storm. The cohousing gardens have a dedicated pile of seaweed with a tarp under and over it so that we retain the nutrients,” she says. “We use it in several ways. We mix it in with our compost, and mulch with it in the fall. It is particularly great for perennial beds, asparagus, rhubarb, and for root crops. Potatoes love the potassium. And roses also respond really well to seaweed. I put about four to six inches on top....The only thing I don’t put it around are leafy plants, like lettuce that is still growing.”
Lynn also uses seaweed to make a root cellar in her garden. She places wool rugs from the thrift store over her root vegetable beds and then piles leaves on top and seaweed on top of the leaves. She says, “This keeps the soil moist while delivering key nutrients to the dirt they are in.” She says that different types of seaweed have their pluses and minuses. Some are a little smelly; others decompose more quickly. “Real seaweed – the laminarias, like kelp – breaks down beautifully and brings moisture, air, and trace minerals to the soil. Eelgrass makes a really great mulch.”
But for some, collecting and transporting heavy seaweed from beach to garden is just not possible. Tom Clark, the grounds manager for Polly Hill Arboretum in West Tisbury, says, “I wish we could use seaweed, but we are not close enough to the ocean for it to be feasible.” Instead they use chopped-up leaves for mulching. “But we do use fish emulsions for seedlings and transplants. It gives them an extra boost and support.” Rebecca Miller of North Tabor Farm in Chilmark echoes Tom, “We don’t have time or gear to collect enough seaweed to cover our fields,” she says. “Instead we use Neptune’s Harvest mixed with a splash of fish oil as a foliar spray a couple of times for all of our seedlings in the greenhouse. And we dip our tomato plants’ roots in the fish emulsion. They thrive when we use it.”
Fish emulsion does seem to be the answer for those who want the benefits of the sea and are working on a large scale or just need an efficient way to deliver the rich nutrients from fish and seaweed to their soil. In fact, while there are many excellent fish- and seaweed-based fertilizer products on the market – Coast of Maine’s Quoddy Blend Lobster Compost, Planet Natural’s Fish Meal, Dr. Earth’s Fish Bone Meal – most of the farmers, gardeners, and landscaping services here on the Island use Neptune’s Harvest organic fertilizers, which are manufactured in nearby Gloucester. They not only use them for their seedlings and as a foliar spray to support vegetables, but also to feed flower beds, and even lawns. Chris Fischer says, “It’s expensive, but it’s excellent stuff.”
Lynn Weber, one of the few who does not use fish emulsion, says, “I don’t need it. There are so many other ways to fertilize the soil here.” Which brings us back to Liz Packer’s point: We’re fortunate to live in a place where farmers and gardeners still have abundant and, more often than not, free ways to enrich the soil. But as Paul Jackson has seen in his lifetime, if we don’t take care of these resources, we won’t have them – and this magical relationship between the land and the sea – for long.
Seaweed packs a punch
Rodale’s The Complete Book of Composting details seaweed’s impressive lineup of nutritional components: “Seaweed in general – that is a mixture of all those which can easily be found on the shore – contains on the average, per ton 7 pounds of nitrogen compounds, 2 pounds of phosphoric acid, 22 pounds of potash, 36 pounds of sodium chloride, and about 400 pounds of organic matter. Barnyard manure, for comparison, may contain per ton 11 pounds of nitrogen, 6 pounds of phosphoric aid, 15 pounds of potash, and 380 pounds of organic matter.” Seaweed even has vitamin B12 – the first known plant to be a source for this vitamin.
