Coir (/ˈkɔɪər/), also called coconut fibre, is a natural fibre extracted from the outer husk of coconut and used in products such as floor mats, doormats, brushes, and mattresses. Coir is the fibrous material found between the hard, internal shell and the outer coat of a coconut. Other uses of brown coir (made from ripe coconut) are in upholstery padding, sacking and horticulture. White coir, harvested from unripe coconuts, is used for making finer brushes, string, rope and fishing nets. It has the advantage of not sinking, so can be used in long lengths in deep water without the added weight dragging down boats and buoys.
Coir must not be confused with coir pith, which is the powdery and spongy material resulting from the processing of the coir fibre. Coir fibre is locally named 'coprah' in some countries, adding to confusion. Pith is chemically similar to coir, but contains much shorter fibers. The name coco peat may refer either to coir or the pith or a mixture, as both have good water-retaining properties as a substitute for peat.
The name coir comes from கயிறு (kayiru), കയർ (kayar), the Tamil and Malayalam words respectively for cord or rope (traditionally, a kind of rope is made from the coconut fibre). Ropes and cordage have been made from coconut fibre since ancient times. The Austronesian peoples, who first domesticated coconuts, used coconut fibre extensively for ropes and sennit in building houses and lashed-lug plank boats in their voyages in both the Pacific and the Indian Oceans.
Later Indian and Arab navigators who sailed the seas to Malaya, China, and the Persian Gulf centuries ago also used coir for their ship ropes. Arab writers of the 11th century AD referred to the extensive use of coir for ship ropes and rigging.
A coir industry in the UK was recorded before the second half of the 19th century. During 1840, Captain Widely, in co-operation with Captain Logan and Thomas Treloar, founded the known carpet firms of Treloar and Sons in Ludgate Hill, England, for the manufacture of coir into various fabrics suitable for floor coverings.
Coir fibres are found between the hard, internal shell and the outer coat of a coconut. The individual fibre cells are narrow and hollow, with thick walls made of cellulose. They are pale when immature, but later become hardened and yellowed as a layer of lignin is deposited on their walls. Each cell is about 1 mm (0.04 in) long and 10 to 20 μm (0.0004 to 0.0008 in) in diameter. Fibres are typically 10 to 30 centimetres (4 to 12 in) long. The two varieties of coir are brown and white. Brown coir harvested from fully ripened coconuts is thick, strong and has high abrasion resistance. It is typically used in mats, brushes and sacking. Mature brown coir fibres contain more lignin and less cellulose than fibres such as flax and cotton, so are stronger but less flexible. White coir fibres harvested from coconuts before they are ripe are white or light brown in color and are smoother and finer, but also weaker. They are generally spun to make yarn used in mats or rope.
The coir fibre is relatively waterproof, and is one of the few natural fibres resistant to damage by saltwater. Fresh water is used to process brown coir, while seawater and fresh water are both used in the production of white coir.
The fibrous husks are soaked in pits or in nets in a slow-moving body of water to swell and soften the fibres. The long bristle fibres are separated from the shorter mattress fibres underneath the skin of the nut, a process known as wet-milling.
The mattress fibres are sifted to remove dirt and other rubbish, dried in the sun and packed into bales. Some mattress fibre is allowed to retain more moisture so it retains its elasticity for twisted fibre production. The coir fibre is elastic enough to twist without breaking and it holds a curl as though permanently waved. Twisting is done by simply making a rope of the hank of fibre and twisting it using a machine or by hand.
In 2009, researchers at CSIR's National Institute for Interdisciplinary Science and Technology in Thiruvananthapuram developed a biological process for the extraction of coir fibre from coconut husk without polluting the environment. The technology uses enzymes to separate the fibres by converting and solubilizing plant compounds to curb the pollution of waters caused by retting of husks.
Because coir pith is high in sodium and potassium, it is treated before use as a growth medium for plants or fungi by soaking in a calcium buffering solution; most coir sold for growing purposes is said to be pre-treated. Once any remaining salts have been leached out of the coir pith, it and the cocochips become suitable substrates for cultivating fungi. Coir is naturally rich in potassium, which can lead to magnesium and calcium deficiencies in soilless horticultural media. Coir fiber is rarely used as a potting material, except for orchids, and does not need buffering, as it has a very low cation-exchange capacity (CEC) capacity, hence not retaining salts.
Coir does provide a suitable substrate for horticultural use as a soilless potting medium. The material's high lignin content is longer-lasting, holds more water, and does not shrink off the sides of the pot when dry allowing for easier rewetting. This light media has advantages and disadvantages that can be corrected with the addition of the proper amendment such as coarse sand for weight in interior plants like Draceana. Nutritive amendments should also be considered. Calcium and magnesium will be lacking in coir potting mixes, so a naturally good source of these nutrients is dolomitic lime which contains both. pH is of utmost importance as coir pith tends to have a high pH after some months of use, resulting in plant stunting and multiple deficiencies. Coir also has the disadvantage of being extremely sensitive to the Leucocoprinus greenhouse fungus. The addition of beneficial microbes to the coir media have been successful in tropical green house conditions and interior spaces as well. However, it is important to note that the fungi will engage in growth and reproduction under moist atmospheres producing fruiting bodies (mushrooms).
Bristle coir is the longest variety of coir fibre. It is manufactured from retted coconut husks through a process called defibering. The coir fibre thus extracted is then combed using steel combs to make the fibre clean and to remove short fibres. Bristle coir fibre is used as bristles in brushes for domestic and industrial applications.
Red coir is used in floor mats and doormats, brushes, mattresses, floor tiles and sacking. A small amount is also made into twine. Pads of curled brown coir fibre, made by needle-felting (a machine technique that mats the fibres together), are shaped and cut to fill mattresses and for use in erosion control on river banks and hillsides. A major proportion of brown coir pads are sprayed with rubber latex which bonds the fibres together (rubberised coir) to be used as upholstery padding for the automobile industry in Europe. The material is also used for packaging.
The major use of white coir is in rope manufacture. Mats of woven coir fibre are made from the finer grades of bristle and white fibre using hand or mechanical looms. White coir also is used to make fishing nets due to its strong resistance to saltwater.
In agriculture and horticulture, coir is used as an organic and decorative component in soil and potting mixes. Due to the increasing concern regarding the sustainability of producing sphagnum (peat moss) and peat from peatlands, usage of alternative substrates has been on the rise; the byproduct coir is one commonly used substitute. Many sources of coir however are heavily contaminated with pathogenic fungi, and the choice of the source is important. Coir is also useful to deter snails from delicate plantings, and as a growing medium in intensive glasshouse (greenhouse) horticulture.
Coir is also used as a substrate to grow mushrooms. The coir is usually mixed with vermiculite and pasteurised with boiling water. After the coir/vermiculite mix has cooled to room temperature, it is placed in a larger container, usually a plastic box. Previously prepared spawn jars, usually grown using substrates such as rye grains or wild bird seed, are then added. This spawn is the mushrooms mycelium and will colonize the coir/vermiculite mix eventually fruiting mushrooms.
Coir fibre pith or coir dust can hold large quantities of water, just like a sponge. It is used as a replacement for traditional peat in soil mixtures, or, as a soil-less substrate for plant cultivation. It has been called "coco peat" because it is to fresh coco fibre somewhat like what peat is to peat moss, although it is not true peat.
Coir waste from coir fibre industries is washed, heat-treated, screened and graded before being processed into coco peat products of various granularity and denseness, which are then used for horticultural and agricultural applications and as industrial absorbent.
Due to its superior absorption capabilities when compared to products made of clay, silica and diatomaceous earth-based absorbents, dry coconut coir pith is gaining popularity as an oil and fluid absorbent. Many other absorbents have to be mined, whereas coconut coir pith is a waste product in abundance in countries where coconut is a major agriculture product.
Coconut fiber (coir) is used as a construction material because the natural fibers are eco-friendly. Additionally, coconut fiber (CF) is resistant to thermal conductivity, is very tough, ductile, durable, renewable and inexpensive. It was observed in an experimental study that by partially replacing 2% of cement with CF, the compressive strength of the concrete is increased.
On the other hand, coir can also contain beneficial life-forms. Coconut coir from Mexico has been found to contain large numbers of colonies of the beneficial fungus Aspergillus terreus, which acts as a biological control against plant pathogenic fungi. Trichoderma is a naturally occurring fungus in coco peat; it works in symbiosis with plant roots to protect them from pathogenic fungi such as Pythium. 2b1af7f3a8