Kelp farming, commonly referred to as ocean farming, seaweed farming, or even 3D ocean farming, is an environmentally beneficial and sustainable method of growing kelp. Large brown seaweeds called kelp are utilized for a variety of products, including food, fertilizers, animal feed, nutraceuticals, biomaterials and more. Due to its ability to address nutritional and environmental issues, kelp farming has become more and more popular in recent years. This is especially true in Maine, where there is already a thriving waterfront infrastructure and a large number of fishermen who operate on the water on a daily basis. 

Here at Nautical Farms, we get a lot of questions about how you farm kelp so we are aiming to address some of the key questions we get in this blog post. Before we get to the nitty gritty on the methods of farming kelp, let’s discuss what kelp is, the brief history of kelp farming both worldwide and in Maine, and the benefits of kelp farming.

what is kelp?

Kelp, a type of large brown seaweed. It is renowned for its rapid growth, high nutritional value, and various industrial applications. It is a valuable resource that has been harvested from natural populations for centuries. In Maine, the seas naturally support a variety of kelp species, such as sugar kelp, skinny kelp, winged kelp, and even shotgun kelp. We’ve written previous blogs answering the question “What is kelp?” so if you’re curious to dive deeper into the kelp sea vegetables, we highly recommend you read that post. Additionally, we’ve written a blog discussing many Maine seaweeds that are not just kelps which can be found here. 

history of kelp farming

Seaweed has been farmed for millennia in China, Japan, and South Korea, among other coastal towns worldwide, where kelp cultivation originated. Traditional kelp farming methods involved attaching bamboo rafts or ropes to the seafloor, allowing kelp to grow naturally on these substrates. The basis for contemporary kelp farming methods were established by these earlier methods. 

In the middle of the 20th century, the idea of kelp farming spread to Western nations, and since then, kelp cultivation technology has advanced significantly. These days, kelp farming is used to protect marine ecosystems, reduce ocean acidity, and store carbon in addition to providing sustainable food and fuels.

the history of kelp farming in maine

Maine has only recently become involved in kelp farming in the early 2000s. It developed in response to the demand for sustainable alternatives that would support Maine's functioning waterfronts and provide other sources of income for people who fish for lobster. With its vast coastline and frigid, nutrient-rich seas, Maine has proven to be a perfect place to cultivate kelp. Pioneering people and groups that created the first kelp farms and investigated cutting-edge farming methods gave the sector a boost. These pioneering efforts created the foundation for Maine's rise to prominence in the expanding seaweed farming industry, boosting the state's economy and encouraging environmentally friendly methods.

the benefits of kelp farming

Kelp farming offers numerous benefits, making it an attractive and sustainable industry. Some key advantages include:

environmental benefits:

• Carbon Sequestration: In an effort to slow down global warming, kelp helps to collect and store atmospheric carbon dioxide (CO2).
• Restoration of Habitat: Kelp farms can act as man-made reefs, offering food and shelter to marine life while boosting biodiversity.
• Nutrient Uptake: By lowering the amount of extra nutrients in the water, kelp helps lessen problems like nutrient pollution and toxic algal blooms.

nutritional value:

• A great source of nutrition, kelp is high in vitamins, minerals, and important elements including iron, calcium, and iodine.
• It is a healthy supplement to many diets because it is low in calories and a source of dietary fiber.

economic opportunities:

• In coastal towns, kelp farming offers employment and revenue prospects.
• It boosts regional and national economies by selling kelp products.

sustainable agriculture:

• Freshwater or arable land are not necessary for the sustainable practices of kelp cultivation.
• Because it doesn't utilize artificial pesticides or fertilizers, it has less of an influence on terrestrial ecosystems.

Now, let’s get into how kelp is farmed. Because we are a Maine-based kelp farm, we are going to focus on the most common method here but know that there are a variety of techniques used to farm kelp worldwide, and depending on our location, you may be interested in exploring other options. 

how to farm kelp

The most common method for farming seaweed in Maine is longline grid farming. Longlines are a common name for lobster ropes that are often used and consist of ropes being strung horizontally, suspended between buoys. The buoys float at the surface of the water and large anchors or moorings that are on the ocean floor. 

The longlines are “seeded” with kelp spores in the fall or winter and are suspended roughly 6 ft below the surface of the water for growing species like sugar kelp or alaria although the depth can vary depending on species and optimal growing conditions. 

This system is used to create a grid structure underwater and above water simply looks like a series of buoys floating in the ocean, often very similar to lobster buoys. 

In the spring, ropes are hoisted up from the water onto a large boat - commonly a lobster boat - and draped across the side of the boat or down the middle of the boat. The kelp hangs similar to a curtain and is then easily cut off the rope and placed into totes or large bags to be transported to the next phase of production. 

Some farms also practice what is called polyculture farming or multi-trophic aquaculture which integrates other forms of aquaculture such as shellfish or finfish. Because kelp helps to extract excess nutrients from the water, the co-cultured species benefits and improves the overall ecosystem health. 

challenges in kelp farming

Although many people believe that kelp farming is simple and has a lower entrance barrier than some other working waterfront occupations, it is not without its difficulties. We won't go through them all here, but we will highlight a few that are crucial to take into account if you're thinking about a career in kelp farming. First off, the east coast farms operate in the winter, when circumstances are sometimes quite difficult, with lots of snow, ice, and strong winds. 

Depending on the equipment, region, and end-of-market strategy, certain harvesting and processing techniques can also prove to be difficult for certain farmers. These techniques can be expensive or labor-intensive. It's crucial to find a customer for the kelp before you begin the growth process. 

Getting the go-ahead from other professions and nearby landowners, in addition to navigating the legal and regulatory requirements, can occasionally be difficult. 

If you are interested in a future of kelp farming, we suggest learning from others, and doing the research ahead of jumping in. There are many great resources available such as GreenWave’s Ocean Farming Hub, Maine Sea Grant, Maine Aquaculture Association, as well as books like Bren Smith’s “Eat Like a Fish” to name a few.