How To Harvest Seaweed To Use In Your Garden


The author’s garden on a misty spring day. A quince tree surrounded by straw colored seaweed is just beginning to leaf out. Row beds, covered with seaweed the previous fall, are a richer brown, being further along in the decomposition process.

Last January, following a fast-paced fall working in Paris, I returned to Newport ready to reconnect with my coastal home and the natural rhythm it inspires. And so, I made it a daily practice to walk Second Beach with my dog, Wrangler. Whether under snow or heavy winds, damp air, or glorious sunshine, the beach was a different place each day. But there were three things you could always find there: me, my dog, and piles upon piles of odiferous, rotting seaweed.


Newport’s seaweed problem: Is it really so bad?

Yes, the same macroalgae that plague our beaches, infiltrate our swimsuits, tangle our hair, and scare away our summer visitors spend most of the fall and winter accumulating along the high tide lines of our crescent beaches. And with the seasonal retirement of the Barber Surf Rake (the specialized tractor that combs Second Beach all summer), the seaweed is left to encroach upon our shores in the off season.

Is this every islander’s worst nightmare? Perhaps not. This article would suggest otherwise, as would the small army of gardeners and farmers who flock to the beach to scoop, shovel, and fork the stuff by the truckload each year.


“It’s a great nutrient source for any garden,” says local horticultural expert Martin Van Hof of Island Garden Shop, who lists nitrogen, phosphorus, and potassium among the macronutrients that seaweed contains, as well as micronutrients (or trace elements) like copper, iron, iodine, and molybdenum. Moreover, it’s a garden resource that is totally free – minus a little sweat.

Since I had recently removed a large swath of lawn from my backyard in the hopes of one day growing food, my overly compacted, depleted soil was in desperate need of nutrients, minerals, and organic bulk. So, every day after my walk, I would leave Wrangler to doze in the sunlight on the truck’s front seat, grab two buckets and a pitchfork from the back, and harvest a few loads, later spreading it on the bare earth of my dormant garden.


A thick topdressing of seaweed glows ruby red against the delicate, semi-evergreen leaves of lavender in the author’s herb bed.


Citizens of Seaweed

Although the reaction of onlookers ranged from curious to incredulous (“What are you doing with that seaweed!?” was a common question shouted at me), I quickly found that I was not alone. I had joined a small community of  seaweed regulars, who came with their own varied method of harvesting: wheelbarrows, tarps, even a family who made it an outing with their small children.

Rhode Island’s constitution calls out the right of citizens to forage seaweed from public shorelines.

In fact, for generations Aquidneck islanders have harvested seaweed to enrich the soil of their gardens, farms, compost piles, and lawns. In doing so, they’re exercising their right as Rhode Island citizens: Section 17 of our constitution specifically defends the right to forage seaweed from public shorelines.

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By late winter, the seaweed on Second Beach fades to a brilliant, straw yellow, as it will in the garden, too.

One nostalgic beachgoer told me that his father, a farmer in Middletown, used to bring a horse and wagon down to Sachuest each fall then spread the seaweed on his fields. Martin of Island Garden recounted that his father’s first job in the 1930s was to harvest seaweed in fall and spread a thin coating on lawns, where it would leach nutrients into the turf throughout the winter before it was raked off and composted in the spring. And last winter, members of Sustainable Aquidneck – a nonprofit that runs a community garden on Green End Avenue and the composting program at the local farmers’ market – could be seen hauling a few loads for their compost heaps. As a green material that’s quick to decompose, seaweed makes a great compost activator, generating heat and spurring on the breakdown process throughout the pile.

You might also like: In the Studio with Mary Chatowsky Jameson, Seaweed Artist


That smell though.

I suppose the most obvious drawback to spreading swaths of seaweed across your backyard is, of course, the odor. But in cold weather, the smell lasts just a few days (though it may return temporarily after a heavy rain). Call me bonkers, but I actually happen to like that low tide smell – in small doses anyway. It reminds me of summer trips to Maine, coming home to the coast after a long time away, and late night dinghy rides across Newport Harbor. And, as winter progresses, the seaweed’s hues change from ruby red to a startling hay yellow. And baby, when its cold outside, any reminder of summer – whether it’s a whiff of the sea or a splash of cheery color – is always welcome in my home. Bonus points if it’s also sustainable, organic, and completely free.

When its cold outside, any reminder of summer is always welcome in my home.



Ready to try seaweed harvesting for your garden? Here’s how.

If you want to try harvesting seaweed for your garden, here are some tips to get you started:

1. Harvesting can be hard work.
Either plan to do one big load with a few extra hands, or else keep some large, sturdy trash bags or 5 gallon buckets with lids in your car, and pick up a little at a time.

2. Surfer’s end is a great place to gather seaweed.
You can park your car close by, and make use of the boat ramp if you plan to wheel your haul up from the beach. Plus, there’s a pretty consistent supply of seaweed right there throughout the off season.

3. Avoid storm pipes and frequently closed areas.
Avoid harvesting from areas that are frequently closed due to combined storm and wastewater overflow. The seaweed can trap fecal coliform bacteria and chemical contaminants as storm water runs off into the bay.

4. Rinse it off.
Soil experts note that the amount of salt on seaweed is negligible. Still, it’s a good practice to rinse off the seaweed before spreading it on garden beds or in compost; the salinity could build up with regular applications, and earthworms are discouraged in the presence of salt. If hosing off your haul isn’t convenient, aim to harvest seaweed from the high tide mark just after a rainstorm.


Along with the seaweed, harvesting at the beach might bring a little sand along for the ride. In Newport, where soil can tend toward a clay consistency, a little sand is a welcome addition that will help to improve soil structure, aeration, and drainage.

5. Seaweed can be applied directly to beds in the fall and winter.
A dense mat of several inches will act as mulch, preventing soil erosion, retaining moisture, and leaching nutrients into the soil below. It will also form an attractive topdressing that will fade from ruby red to straw yellow to brown. Depending on the weather each winter, the seaweed may break down completely by spring, or else need to be turned in or removed and thrown in the compost before spring planting.

6. You can also use seaweed as a compost activator.
Seaweed works great as the “green” material that will decompose quickly and form a warm sludge, which encourages the more fibrous, dry “browns” of the compost to decompose in turn. I’ve heard that layering seaweed into the compost, like making a lasagna, will discourage pests from taking an interest in food waste.

For more home composting tips, check out Sustainable Aquidneck’s composting guidelines.



👂🏻's in the 💨🌾🌾🌾

A post shared by Caroline Goddard (@hopestatestyle) on

Above, the author’s harvesting assistant, Wrangler, a Paws New England rescue, on his daily Second Beach walk. He’s currently very excited that it’s almost October 1, when dogs are officially welcomed back on Middletown’s beaches.

Caroline Goddard is a photographer, writer, and the blogger behind Hope State Style. A proud Rhody native with a degree in Visual Arts from Brown, she loves telling tales in images, focusing her camera on regional culture and off-beat, indy weddings. One part earth child, one part wanderer, she divides her time between Newport – where she's starting a tiny backyard farm – and the rest of the world. Recent travels have taken her to Paris; Reykjavik; and Paros, Greece. But since she just ordered a dozen fruit trees for her yard, she's probably going to stick around for a bit. Follow her adventures via Instagram @hopestatestyle.

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