How We Safely, Sustainably and Ethically Harvest Seaweed.

Seaweed harvesting is often described as simple. You go to the shore, find the seaweed, cut it, bring it home.

In reality, good seaweed harvesting is much more thoughtful than that.

At The Cornish Seaweed Company, we work with the tides, the seasons, the coastline and the living ecosystem around us. Our seaweed is hand-cut from the wild Cornish coast, with care taken not only over what we harvest, but how, when and where we harvest it.

That matters because seaweed is not just an ingredient. It is habitat. It is shelter. It is part of the rhythm of the shore. It provides food and protection for many small marine species, and it plays an important role in coastal ecosystems.

So when we talk about sustainable seaweed, we are not just talking about the finished product in your kitchen. We are talking about the whole journey from rock pool to plate.

Harvesting with permission, care and responsibility

The first part of responsible seaweed harvesting is making sure it is done properly and legally.

We are fully licensed to harvest seaweed by Cornwall Council and the Crown Estate, with sustainability and approval from Natural England forming part of that licensing process. The Cornish Seaweed Company was also involved in helping Natural England establish the Code of Conduct for Seaweed Harvesting, which sets out guidelines to make sure harvesting is carried out without significantly impacting the ecosystem.

This means our harvesting is not guesswork. It is managed, considered and based on a clear set of principles.

Our approach is simple: harvest by hand, take only part of the plant, avoid disturbing wildlife, work with the active growing season, and rotate harvesting areas so the shore has time to recover.

It is a slower way to work, but that is exactly the point.

The seaweed “haircut”

One of the easiest ways to understand sustainable harvesting is to think of it as giving the seaweed a haircut.

We do not pull seaweed up from the rocks. We do not strip whole areas bare. We cut carefully, leaving the holdfast attached so the seaweed can continue to grow.

The holdfast is the part that anchors many seaweeds to the rock. If this is removed, the seaweed cannot regrow in the same way. By cutting above the growing point and leaving the base intact, the plant has the chance to recover.

This is especially important with species such as kelp and sea spaghetti, where the growing point needs to be understood before cutting. Sea spaghetti, for example, grows from the tips of the frond, so it should be harvested by cutting only a few fronds from each plant and leaving enough behind for continued growth.

With other species, such as dulse and sea lettuce, the cutting method is slightly different, but the principle stays the same: take a modest amount, cut cleanly, and leave enough behind for the plant and the wider ecosystem.

Why we harvest by hand

All of our seaweed is harvested by hand from the Cornish coast.

This is important because hand harvesting allows us to be selective. We can see what we are cutting. We can avoid seaweed that is home to other species. We can leave younger plants, damaged plants or areas that need more time to recover.

It also means we can avoid unnecessary disturbance to the shoreline.

Seaweed beds are busy places. Among the fronds and rocks you may find small crustaceans, molluscs, sea snails, limpets, fish, anemones, eggs and other marine life. A responsible harvester needs to look closely, move carefully and treat the shore as a living place, not a crop field.

That is why one of our core promises is that other wildlife should not be disturbed during harvesting.

Working with the tides and seasons

Seaweed harvesting depends on timing.

Different seaweeds grow in different parts of the shore, and many are only easy to reach around low tide. Some species grow higher up the intertidal zone, while others are found lower down, where they are exposed only during spring tides.

This natural zonation is part of what makes seaweed so fascinating. The upper shore is home to hardier species that can cope with being out of the water for longer. The middle shore supports a wider mix of species, including wracks, dulse, sea lettuce and pepper dulse. The lower shore is where you are more likely to find kelps, Irish moss, sea spaghetti and other species that spend more time underwater.

For harvesting, this means knowing the tides is essential.

Spring low tides are often the best time to harvest because more of the shore is exposed. This gives us access to species that are usually underwater, while also allowing time to move carefully, cut properly and leave the shore safely before the tide returns.

The seasons matter too. We harvest seaweeds during their active growth season where possible, because this gives them the best chance to recover quickly.

Rotating harvesting areas

Sustainable harvesting is not only about how much you take from one plant. It is also about how often you return to the same place.

That is why we rotate harvesting areas.

After an area has been harvested, it is given time to recover. Depending on the species and the location, harvested areas may be left for several years before being harvested again.

This helps protect the long-term health of wild seaweed populations and the habitats they support.

It also reflects one of our central sustainability principles: seaweed should be harvested in a way that maintains the productive capacity of wild populations and supports their long-term use.

Clean waters matter

Where seaweed is harvested matters just as much as how it is harvested.

Seaweed naturally absorbs nutrients from the water around it. This is one of the reasons it is such an interesting and valuable food. But it also means harvesting location is important.

Seaweed should never be collected from areas close to sewage outlets, harbours, industrial sites, towns, run-off points or polluted streams. Seaweeds found loose on the beach or lying around the high-tide mark should also be avoided, as they may already be decomposing.

Our seaweed is harvested from pristine Cornish waters on the Lizard Peninsula, and we work closely with local environmental bodies to support biodiversity and the health of the coastline.

We are also certified organic, and our sustainability pledge includes working to Soil Association and MSC environmental standards for sustainable harvesting and seaweed farming.

Safety on the shore

The seashore is beautiful, but it can also be unpredictable.

Good harvesting starts with safety. That means checking the tide times, understanding the local shoreline, watching the weather, wearing suitable footwear and never taking unnecessary risks.

Rocks covered in seaweed can be extremely slippery. The tide can come in quickly. Some growing locations are remote, with poor phone signal and difficult access. For this reason, it is always sensible to let someone know where you are going, carry a charged phone, avoid harvesting in poor weather, and go with another person where possible.

This is especially important for anyone foraging for seaweed recreationally. Seaweed foraging can be enjoyable and rewarding, but it should always be approached with knowledge, caution and respect.

Foraging and sustainability

Foraging for seaweed is not about taking as much as you can carry.

The key principle is to harvest in a way that allows the seaweed to regrow and avoids damage to the surrounding ecosystem.

That means:

• Only harvesting what you need.
• Cutting with scissors or a sharp knife.
• Leaving the holdfast attached.
• Avoiding clear-cutting an area.
• Not trampling sensitive species.
• Avoiding seaweed that is carrying other creatures or eggs.
• Leaving plenty behind for wildlife and future growth.

For private foraging, it is also important to understand that land ownership and harvesting rights can be complicated. In many places, permission may be needed from the relevant landowner or authority. Rules can vary depending on location, so it is always worth checking before collecting seaweed.

For anyone new to seaweed, learning where different species grow, when they are in season and how to harvest them properly is essential. Our Seaweed Cookbook includes guidance on seaweed ecology, shore zones, tides, cutting methods, safe foraging and how to prepare fresh seaweed at home.

From harvest to kitchen

Once seaweed has been harvested, it needs to be handled properly.

Fresh seaweed should be rinsed to remove sand, shells and small sea creatures. Some seaweeds may be eaten fresh, while others are best dried, flaked, powdered or stored for later use.

Drying is one of the best ways to preserve seaweed. It extends shelf life, makes it easier to store and concentrates the flavour. Once dried, seaweed can be flaked or powdered and used in everyday cooking.

Storage matters too. Dried seaweed should be kept in a cool, dark, dry place in an airtight container, as seaweeds naturally attract moisture.

This careful treatment is part of making the most of the harvest. If seaweed has been collected thoughtfully, it should be used thoughtfully too.

Why it matters

Seaweed is one of the most naturally abundant, flavourful and useful ingredients we have around our coastline.

It does not need fertilisers, pesticides or fresh water to grow, and it plays a role in healthy marine ecosystems. But those benefits only matter if seaweed is harvested with care.

For us, harvesting is about more than gathering an ingredient. It is about respecting the shore, protecting wild populations, supporting biodiversity and helping more people understand the value of the food growing around our coast.

Every handful of seaweed has a story behind it: the tide, the season, the species, the cut, the place and the care taken to bring it from the ocean to your plate.

That is why we harvest slowly, by hand and that is why sustainability will always be at the heart of what we do.