Cotton is the most widely used natural fibre because it has several special properties. Cotton is soft and absorbent, which is great for next to the skin garments; it also takes dyes well and is very durable. Cotton seems to be a perfect fibre but, growing cotton has several serious environmental and ethical issues.
Cotton comes from the fluff around the seed in the cotton boll, unlike linen and hemp which come from the stems of these plants. The technical name for this fluffy fibre is lint. A cotton boll has about 250,000 cotton fibres. Depending on the variety of cotton, each fibre is between 1 and 6 cm long.
The word cotton comes from the Arabic ‘al qutn’; the Spanish word is very similar ‘algodon’. The Germans call it ‘Baumwolle’ which means tree wool. In Russia they use the word ‘khlopok’, which sounds similar to kapok, another lint fibre.
A) Why is cotton so popular?
The high cellulose content and the shape of the cotton fibre make cotton very special. If you look under the microscope, a cotton fibre is kidney-shaped in cross section and is a twisted ribbon with about 60 revolutions per centimetre. The end of the fibre that was joined to the seed has many small tendrils, like the fingers of a hand holding a ball; the other end is tapered. As a result, cotton has several properties that make it very popular:
Most plant fibres consist mainly of cellulose and a small percentage of lignin. Lignin is woody, and therefore not soft. Jute, for example, has about 60% lignin, linen about 3%, whilst cotton has no lignin. Unlike other plant fibres, cotton is almost pure cellulose, making it very soft.
Cotton is very good at attracting and holding water, so it is very absorbent.
Its main component, cellulose has a large number of places that can bond with moisture, therefore cotton can absorb up to 27% of its weight in water. Nylon, which has many less bonding places, can only absorb 10% of its weight of water.
The cotton tendrils pull liquid in by capillary action and hold the liquid in the spaces between the tendrils.
Cotton is a hollow fibre, and moisture can fill the hollow centre. When growing the cotton fibre was oval in cross section, but as it dries it becomes kidney shaped, rather like a fat ‘U’. In contact with moisture, it expands again and holds a lot of water.
- Easy to dye
As well as being good at attracting water, cotton is good at attracting dyes, making it easy to dye. It also has excellent colour retention.
Cotton does not have any sharp bits, synthetic fibres on the other hand often have sharply cut ends which can irritate the skin and cause itchiness.
The cotton fibre has a tapered end that makes it a very comfortable fibre to wear next to the skin.
Cotton is strong and durable and resists tearing. It also resists abrasion, pilling and moth damage.
Cotton has high tensile strength, which means it can withstand high pulling pressure resulting in fewer breakages during spinning of thread and weaving of fabric.
Cotton is stronger when wet.
Of course all this depends on the type of cotton used, and the type of weave. Long staple cotton such as Sea Island cotton, with fibres up to 6 cm long, is stronger than other varieties of cotton. Tightly woven twill used in jeans is stronger than finely woven batiste fabric.
- Easy to sew
Woven cotton is easy to cut and sew as the fabric doesn’t slip or stretch that much.
B) Biology of Cotton
Cotton fibre is produced from plants of the genus Gossypium of the mallow family, Malvaceae. The cotton plant produces large showy, white, creamy or yellow flowers that fall off leaving a large capsule or a cotton boll that contains both the seeds and a mass of white, downy cotton fibres. A sunny environment with little frost and enough rainfall is needed to grow cotton successfully. Cotton is a perennial plant, but it is grown as an annual to avoid pest and diseases.
You can grow cotton plants in a sunny windowsill in the UK although it might only produce cotton in its second year. However, it is very exciting to see the capsule forming and then splitting open like popcorn, full of soft cotton fibre.
C) History of Cotton
The genus Gossypium probably originated in Africa 150 million years ago. The splitting up of Gondwanaland and the separation and formation of the present continents then caused the separation and subsequent development of different Old and New World cotton species and varieties.
Cotton has been found in Mexican caves (Tehaucan valley) dating back to about 3500 BC and there is archaeological evidence from the Indus valley (Mohenjo Daro) of Pakistan from 2700 BC and from Peru in 2500 BC. These three sites are likely to have been original centres of cotton cultivation.
Cotton cultivation in the Old World began from India and Pakistan, where cotton may have been grown for more than 6,000 years and was gradually exported to Mesopotamia, Egypt and surrounding countries.
Cotton was adopted much more slowly into Europe, but during the late medieval period, cotton became a commonly imported fibre to northern Europe.
By the end of the 16th century, cotton was cultivated throughout the warmer regions of Asia and the Americas.
In 2019, the Chinese germinated cotton seeds on the moon, the first ‘truly other-wordly plant in history.’
D) Types of Cotton
There are about 43 species of Gossypium but only 4 are important for cultivation, that is, two species of Old World Cottons from Africa and Asia and two New World Cottons of the Americas.
The four principal species of cotton are;
New World Cottons
- Long staple cotton (Gossypium barbadense) is native to tropical South America and produces a high quality, long staple cotton with fibres of up to 6 cm in length and accounts for 8% of commercial cotton production. You are probably familiar with this cotton as Pima, ‘Sea Island’ (3.5 to 6 cm) and Egyptian (3.8 to 4.4 cm) cottons.
- Upland cotton (Gossypium hirsutum) is believed to have evolved in Mexico and is native to Central America, Mexico and the Caribbean. It produces much shorter fibres of 2 to 3 cm in length but is the most commonly grown cotton and accounts for up to 90% of the world’s commercial production of cotton fibre.
Naturally coloured cotton
Upland cotton comes in more colours than just white. Naturally coloured cotton originated in the Andes around 5000 years ago. Its colours include red, green and several shades of brown. The yields are lower and the fibre is shorter and weaker than white cotton. However, naturally coloured cotton has several advantages.
- It can be grown organically, as it has high resistance to insects and diseases.
- It does not need to be dyed, saving on the cost of dyes and also eliminating toxic dye waste.
- It has very good sun protection properties.
Old World Cottons
- Gossypium herbaceum in Africa and Asia, includes the most primitive cultivated forms of Old World cotton.
- Gossypium arboreum – tree cotton native to India and Pakistan and probably only found in cultivation.
The cotton plant is also a source of cottonseed, which is pressed for oil that is used in salad oils, cosmetics, soap, candles, detergents, and paint, and cottonseed hulls and meal that are used for animal feed.
E) Organic Cotton
Organic cotton is certified to have been grown without synthetic fertilizers or pesticides. Organic cotton plants are also not genetically modified. Organic cotton accounts for only 1% of all cotton production, a tiny percentage.
Companies often use the term ‘organic cotton’ as green wash, in other words as a marketing ploy. Organic cotton may be grown organically, but after that it may have been processed conventionally, negating most of the benefit of having been grown organically. Only cotton with GOTS certificate has been processed organically through the whole process.
Organic cotton has on average a 25% lower yield than conventional cotton, so organic cotton uses more land and more water to produce the same weight of cotton. Organic cotton is a positive initiative, but more research is needed to find out whether it is really more sustainable than conventional cotton.
An alternative to looking for organic cotton is to look for sustainable cotton, which means one or more of the following: organic, FairTrade, cotton made in Africa, or Better Cotton Initiative. However, at present there is more production of sustainable cotton than there is demand, so sustainable cotton has to be sold as conventional cotton, generating less profit for farmers. Also registering in any of these initiatives is costly and small scale farmers cannot afford it. As organic cotton becomes more popular, the prices go down and the farmers have less incentive to grow it, often switching to other more lucrative crops.
F) What is mercerised cotton?
The cotton fibre has many tiny tendrils, which make it fuzzy. As well as helping cotton absorb water, this fuzziness also gives it a soft surface similar to peach skin. If you want shiny cotton, you need to remove the fuzz by a process called mercerisation. Mercerised cotton is chemically treated with a strong lye solution that dissolves the tendrils, making the cotton more lustrous. The colours also look more vibrant in mercerised cotton. However, the fuzz removal makes cotton less absorbent. Lustrous mercerised cotton is good for embroidery thread, it is also good for table mats, which will absorb less stains. Non-mercerised cotton is better for towels for example.
G) Why are cotton T-shirts so cheap?
Cotton is a valuable fibre, and yet cotton clothes can be dirt cheap. Why?
Subsidies leading to unfair competition, together with modern day slavery and a disregard for health and safety make cotton unjustifiably cheap.
China and rich countries such as the USA provide cotton subsidies to their farmers giving them an artificial advantage over farmers in poorer countries. In the USA, for example, cotton subsidies amount to 50% of the actual value of the crop. Cotton is of vital importance to sub-Sahara countries as a source of income, and these countries are very competitive in their cotton production. China on the other hand is a relatively inefficient cotton producer with high production costs.
Linen is considered an expensive fabric. However, if cotton was grown without subsidies and with proper regard to ethical issues, linen, which is a more environmentally friendly fibre, would be much more comparable in price to cotton.
H) Cotton production
30% of all textiles are made of cotton, therefore cotton production is huge. About 25 million tons of cotton is produced every year worldwide, the largest producers being India and China. 2.5% of the world’s arable land is used for growing cotton. This is land that will be needed to offset carbon emissions as the world warms up and to grow food, as the world’s population grows.
I) Environmental and Ethical Issues
Despite being a natural fibre, cotton is a very dirty crop. One kilo of non-organic cotton uses 10 thousand litres of water, and 300 grams of fertilisers and pesticides.
- Water footprint
Cotton requires moderate rainfall. However this crop is often grown in drier areas using irrigation. Cotton is a thirsty crop, requiring more water than other plant fibres. You need 8 to 10 thousand litres of water to produce just one kilo of cotton. Improper irrigation has led to desertification in several areas. The best known example is Lake Aral, which was one of the four largest lakes in the world in 1960. The lake water was used over 50 years by huge cotton farms. Now 90% of the lake is gone, leaving salinated soil which is of no use for agriculture.
Modern slavery is one of the most complicated and challenging problems facing fashion today. Uzbek and Turkmen governments, for example, force thousands of their citizens to temporarily leave their usual jobs and harvest cotton instead. They have to pick a certain amount of cotton otherwise they risk losing their usual job. There are also reports of modern slavery in the textile factories in Leicester, with workers being paid as little as £2.50 per hour.
- Health and safety:
Cotton uses 24% of global insecticide and 11% of pesticides. These toxic substances affect the health of farm workers and people living nearby. Some of the chemicals used are linked to leukaemia and Parkinson’s disease. They may also cause an increase in miscarriages, malformations and cancer
There is a higher incidence of cancer and lung disease in textile workers due to dyes and dust.
J) What you can do
Choose pure cotton rather than mixes. Fabrics that have a percentage of synthetic fibres are no longer biodegradable and are difficult to recycle.
Shirts versus T-shirts
Cotton shirts and T-shirts are made of different types of fabric. Shirts are made of woven fabric which has threads running at 90 degrees to each other (their threads are the warp and weft in a loom). T-shirts on the other hand are made of jersey, which is a type of knitted fabric, made with many interconnecting loops.
In my opinion, cotton shirts are more sustainable than T-shirts. Shirts are more durable because woven fabrics are easy to mend with a patch, whilst the edge of jersey fabric tends to roll, making it difficult to mend.
The life cycle of a shirt is also more sustainable, you can save the buttons for later use in a button jar, and you can give the fabric a new lease of life as patchwork quilts or cushions. There is not much you can use a worn out T-shirt for, apart from cleaning cloths.
It is not difficult to find pure cotton shirts, but T-shirts often come with a percentage of synthetic fibre (e.g. lycra) which makes T-shirts more difficult to recycle than shirts.
- Treat cotton with the respect that this amazing fibre deserves.
- In a gold workshop every piece of gold is precious, and no gold is thrown away. Cotton should be treated like gold, instead of being easily discarded.
- Investigate how to mend clothes to make them last longer. Learn patchwork and quilting to give new life to old clothes.
- You know the saying, a dog is for life, not just Xmas. The same applies to textiles.
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