HOW SEA GRASS WAS USED.

A single tree can support hundreds of different species. It is clear and visible to man and can be easily understood. Less visible and less known around the coast of the British Isles are a group of four flowering sea plants known as sea grass, with the largest of these being Zostera Marina. These plants form meadows mostly in intertidal zones where they, like trees, support a large range of species such as fish, marine mammals, invertebrates and birds. However, what is often unknown is that in the same way that trees are used by man to produce, furniture, paper or even charcoal sea grass has also been used by man.

Seagrass, Zostera Marina has found to have a variety of uses as an insulator, upholstery, packing mattresses, packing for fragile materials, bedding for domestic animals, fertilizer and a soil binder to prevent erosion and even described being used in an Argentinian beef dish where it is called ‘cochayoyo’.

Advert for Sea Grass to be supplied to fill mattresses in the Hospital in St Peter Port on the Isle of Guernsey

Sir Henry Hansen the former President of the Prudential Assurance Company died in1911 and his obituary contained the following note: “During the Lancashire cotton famine in 1852 he devoted considerable time and money to find a substitute for cotton in an extract from the marine plant zostera marina and he read a paper before the British Association on the subject. It was found in the end that the expense would be too great to make any practical value.” [i]

The cotton famine was caused by the American Civil War cutting off the supply of cotton into Liverpool and the Lancashire cotton mills. The fibre could be used instead of cotton but it had several problems that needed more manual labour to solve, that is: separation of fibre from the mucilage of the sea grass; cotton fibre was ½ to 2 inches long whereas zostera marina fibre was  5 to 60 feet long; zostera fibre was more prone to break in processing. An experimental mill was established in Scotland, but this was never commercially viable and was scrapped within two years.

In the 1860’s there are accounts of zostera marina being used on houses on the Irish and Scottish coasts in particular. Leaves of sea grass were dried in the sun until they were bleached white then cut  into lengths a foot long and used as thatch. It was also used as an insulation material dried and shriveled to a consistency similar to modern polystyrene that was used in studded walls of cottages as insulation. It was also used as loft insulation.

In the 1820’s dried zostera marina was recommended as being better than horse hair to stuff upholstery and mattresses as it held no fleas. Indeed, the bleached product was believed to have antiseptic qualities that made it particularly useful for hospital mattresses and cushions and was used into the twentieth century.

In France in the 1880’s paper was made out of zostera marina with balls of fibre from the plant collected from the shores of Majorca and Minorca for that use. The fibre was mixed with wood pulp to make a strong and durable paper, a bit like the use of linen in bank notes.

Dried zostera was also collected from the shores to be used as packing material for fragile items, most notably bottles of wine and spirits exported from France and the Netherlands and for cushioning flasks of acid.

Finally was the use of zostera in agriculture. Cottagers in Ireland, Scotland and Northumberland farmsteads used it locally as a soil conditioner, but in reality it would have little fertilizer value, but would add structure to soils prone to erosion from coastal winds. In Guernsey it was used to protect potatoes from occasional cold temperatures.

In all these uses except the experimental production of cloth as a cotton substitute zostera was gathered off the shores as a natural waste product in the same way that driftwood, sea coal or ambergris has been gathered, a waste product of nature used by man.

[i] The Lancaster Observer and Morecambe Chronicle December 8^th 1911