Historical Use of Seaweeds

Q: (MH) What do we know about the historical use of seaweeds as food in Ireland?

A: (FG) We have records showing that people ate a lot of Dillisk (Palmaria palmata), Laver (Porphyria spp.), Carraigeen Moss (Chondrus crispus and/or Mastocarpus stellatus), and Channelled Wrack (Pelvetia canaliculata) from early medieval times in Ireland, along with shore-gathered shellfish (particularly crabs, oysters and limpets, which I imagine would often have been gathered at the same time as seaweed). Beyond this, we don’t have a lot of information. Phrases like ‘ag baint bearnach’ (gathering shellfish) and ‘ag baint feamainn’ (gathering seaweed) were used in stories recorded by ethnographers, but very little further detail was given in most accounts.

Carraigeen was sold for cash in the Victorian period, for export and use in medicines and food (blancmange and jellies), but I’m not sure how much was used by coastal people in Ireland. Usage (and the names used for different seaweeds) varied a lot from location to location.

Q: (MH) what about seaweed as fertiliser?

A: (FG) The use of seaweed as fertiliser was traditionally seasonal. In Autumn and Spring, a huge amount of seaweed can be washed into some bays, and access routes by pony or donkey and trap were made to allow its exploitation. The right to gather this treasure was a matter of many legal disputes, so we know a bit more about it.

Autumn storms (usually from late September until shortly before Christmas) would bring in a lot of shed kelp fronds, which with most species are naturally loosened by the perennial stipe (stem) at the end of summer. Any attached reds would come with them. Storms would also cast up any other seaweeds — wracks, greens, free-living reds — which weren’t tightly attached to durable rocks or structures. This seaweed would be gathered from the high tide line and put on fallow land (stubble, dug potato fields etc) as mulch.

In late Spring, another ‘fall’ of kelp occurs when Laminaria digitata shed its fronds (this is how it gets the name ‘Mayweed’). Perfect timing for earthing up potato fields or mulching beds of recently-harvested winter cabbage. Poorer people would have had a complicated set of rights to particular, often inaccessible, coves and beaches to gather seaweed, which could be carried away in baskets or panniers carried by people or pack animals. This often involved quite a bit of climbing.

Q: (MH) Was seaweed also gathered to be sold commercially as fertiliser?

A: (FG) The commercial production of fertiliser for sale was a different matter, usually managed by ‘outsiders’ and providing a small source of cash income for coastal people. Because a constant source of brown seaweed was needed to keep production going, it mostly relied on the gathering of Egg Wrack (Ascophyllum nodosum) (confusingly referred to as ‘kelp’ by industry, even though it’s a wrack) from sheltered accessible coves and beaches. This trade lasted until replaced by the commercial production of nitrate fertilisers.