When most people think about kelp farming, they picture something futuristic — ropes in cold water, seaweed growing offshore, maybe a climate-tech startup or two. But kelp farming is not actually new, the history of kelp runs deep (no pun intended). Seaweed cultivation has deep roots in Asia, with active cultivation documented in Tokyo Bay by the late 1600s, where farmers used bamboo branches to collect spores and then moved them into productive estuarine waters. Over time, those methods evolved into rope- and net-based cultivation systems that still shape modern seaweed farming today.
What is relatively new is the rise of North Atlantic sugar kelp farming as a modern food and aquaculture sector. Sugar kelp, Saccharina latissima, is a cold-water brown alga found across the North Atlantic, Arctic, and parts of the North Pacific, and it has become one of the most important edible kelp species under cultivation in the United States. NOAA describes sugar kelp as widely cultivated and eaten in Asia and increasingly popular in the U.S. as a nutritious food high in fiber, vitamins, and minerals.
What is sugar kelp?
Sugar kelp, or Saccharina latissima, is a large brown seaweed in the order Laminariales. It is especially well suited to cold, nutrient-rich waters, which is why it does well in the North Atlantic. In the U.S. and northern Europe, it has become a major focus of commercial kelp farming because it grows quickly in winter and early spring, fits existing shellfish farm calendars well, and has strong potential for food, feed, and biomaterial applications.
That winter-growth pattern is one of the reasons sugar kelp is so interesting from an aquaculture perspective. NOAA notes that sugar kelp is a cold-water or winter crop, which means it can help diversify aquaculture systems rather than directly compete with warm-season production. In practice, this has made it especially attractive in places like Maine, Connecticut, and Alaska, where growers can use existing marine farming expertise and infrastructure to expand into seaweed.
The deeper history: from East Asia to modern aquaculture
Modern seaweed farming owes a lot to East Asia. China, Japan, and Korea built the historical foundation for large-scale edible seaweed cultivation, and today global seaweed production is still overwhelmingly concentrated in Asia. FAO reports that marine and coastal aquaculture produced 36.4 million tonnes of algae in 2022, and a separate FAO seaweed overview notes that Asia accounted for 99.5% of global seaweed production by volume in 2021, with China as the largest producer.
That matters because when people talk about “the future” of kelp farming in North America or Europe, they are really talking about adapting and extending a farming tradition that has already been refined elsewhere for centuries. The North Atlantic industry is not inventing kelp farming from scratch; it is developing a regional version of a much older and much larger marine food system.
How sugar kelp is farmed today
The basic farming process for sugar kelp is elegant and surprisingly low-input. According to NOAA, growers typically begin by collecting wild sugar kelp to extract spores. Those spores are settled onto nylon twine wrapped around PVC spools, held in controlled indoor systems for several weeks, and then transferred to a marine grow-out site where the seeded twine is attached to longlines suspended between buoys. Once the blades reach the right size, the kelp is harvested directly from the line.
That system matters for two reasons. First, it allows farmers to produce a food crop without land, freshwater irrigation, synthetic fertilizer, or feed inputs. Second, it means sugar kelp can slot into working waterfronts and existing coastal economies in a way that is operationally quite different from terrestrial agriculture. NOAA also notes that once sugar kelp is in the ocean, it does not need to be fed because it grows by photosynthesis and nutrient uptake directly from the surrounding water.
Why sugar kelp farming gets so much attention
Some of the excitement around kelp farming is definitely justified. Sugar kelp farming has a relatively light physical footprint compared with many other food systems: NOAA describes the grow-out process as having little disturbance of sediments or aquatic vegetation, with seeding and harvesting both carried out as quick, low-impact operations. NOAA also highlights the ecosystem services kelp can provide, including removal of excess nutrients such as nitrogen and phosphorus, uptake of carbon dioxide, oxygen release during growth, habitat structure for juvenile fish and invertebrates, and some shoreline protection through wave-energy dispersal.
That said, the “kelp will save the world” narrative can get oversimplified. In real farming systems, many benefits depend on site selection, scale, timing, processing, and what actually happens to the biomass after harvest. Kelp farming is promising, but it is not magic. The science and economics are both still developing, especially outside Asia.
The current state of kelp farming in the North Atlantic
The North Atlantic kelp sector is growing, but it is still small compared with the global industry. A 2022 analysis of the U.S. sugar kelp industry described North America as capturing less than 0.1% of the global seaweed market at the time, even though seaweed demand and innovation were increasing. The same paper identified Saccharina latissima as one of the most promising and prevalent cultivated species in the U.S., and noted that Maine and Alaska dominated domestic edible seaweed production, while Connecticut was developing as a more niche but potentially valuable regional market.
That regional framing is important. In the North Atlantic, kelp farming is not one uniform industry. Maine has scale and history, Connecticut has proximity to dense consumer markets, and different producers are pursuing very different strategies: food products, ingredient processing, ecosystem-service narratives, regional branding, and value-added products. The same 2022 study argued that origin labels, eco-labels, and quality grading systems may become increasingly important as the industry matures.
In practical terms, the industry is still in a buildout phase. Maine, for example, was already described in that paper as home to the country’s first commercially viable seaweed farm and the leader in U.S. edible seaweed production. But even there, the sector remained early enough that market differentiation, product development, and processing pathways were still major open questions.
The challenges the industry is still working through
The science of sugar kelp farming has advanced quickly, but commercialization still faces some very real bottlenecks.
One is processing. Raw kelp is bulky, wet, and highly perishable, so the economics often depend on what happens after harvest: drying, freezing, milling, seasoning, fermentation, ingredient extraction, or conversion into consumer-ready foods. Another is market fit. Kelp can be nutritionally impressive and environmentally attractive, but if consumers do not know how to cook it — or if the taste and texture feel too unfamiliar — then demand stalls. A third challenge is site and regulatory complexity, since seaweed farms have to fit into local coastal use patterns, permitting systems, and food-safety expectations.
There are also biological and environmental considerations. NOAA notes that farmed sugar kelp must be monitored for toxins and bacteria, and that kelp can assimilate contaminants present in the environment, even though levels are generally low and monitoring systems are in place. In other words, sugar kelp farming is low-input, but not no-management. It still depends on careful site choice, testing, and environmental oversight.
Why I think sugar kelp still matters
Even with all of those caveats, sugar kelp is still one of the most compelling marine crops out there.
Scientifically, it is fascinating because it sits at the intersection of ecology, aquaculture, food systems, and coastal economies. Commercially, it is interesting because it offers a route to foods and ingredients that are both nutrient-dense and meaningfully different from land-based staples. And culturally, it has a lot of room to grow — especially in the West, where seaweed is still often treated as niche instead of normal.
That is probably the biggest takeaway for me when I look at the history of kelp. It’s truly been around for human history – and yet most American’s have never tried it! Expect perhaps in sushi rolls.
Here at Pasta from the Sea, we’re on a mission to bring kelp to the table, deliciously. If you’re interested in supporting our mission, give Seaghetti a try!
~ Helen