The science bit
Annual or perennial herb or shrub reaching up to 2m tall. Leaves up to 10cm long, heart-shaped (cordate) at base. Flowers yellowish white, fading to pinkish purple. Fruits capsules up to 4cm long; broadly ovoid to subglobose; beaked at tip; 3-5-celled, each cell contains up to 11 copiously hairy and fuzzy seeds. Pollinated by insects.
- The cotton that we use is made from the seed fibres of the plant, which are up to 2.5 inches long and have evolved to help the plant disperse its seeds.
- Cotton is the world’s biggest non-food crop and makes half of the world’s textiles, explosives, oil, cattle food, toothpaste. It has survived competition from synthetics but at the expense of heavy fertiliser and pesticide use and its shocking history of labour exploitation. This elegant, cool popular material has cost more in human misery than its competitors wool, linen and nylon. The cotton trade was a driving force in the Industrial Revolution and helped to finance the British Empire. It was the mainstay of the slave trade and contributed to the American civil war. Today it is the heavy pesticide use necessary to grow this ‘white gold’ that claims lives.
- When Britain became a major cotton cloth maker in the 18th and 19th century, it drove cottage cotton weavers into factory work or into the workhouse. The word 'Luddite' has come to mean someone who hates technology. In fact, the Luddites were textile artisans who protested against the introduction of the machines that put them out of a job by wrecking them. Perhaps the most important technological advance in the history of cotton was the invention of the cotton gin (short for ‘engine’) by the American Ely Whitney in 1793, which reduced the manual labour required to extract cotton seeds.
- More chemicals are sprayed on cotton than on any other crop. Today cotton takes up less than 3% of the world’s farmed land but uses a quarter of the world’s pesticides! Newer safer chemicals have been developed, but they cost more. So, cheaper, more toxic chemicals are used in developing countries, causing about 20,000 unintentional deaths a year.
Where it grows
7,000 years ago humans started growing cotton in the Indus Valley in what is now Pakistan; 2,000 years later it was cultivated in what is now Mexico and Peru. Fragments of cotton fabric from 5,000 BC have been excavated in Mexico and Pakistan. Cotton spread east from Pakistan into China, Japan and Korea and west into Europe, reaching Spain in the 900s.
Long cotton fibres are spun into thread for textiles, towelling, paper, banknotes, fishing nets, tents, nappies, wallpaper, bandages, surgical sutures, rope and sheets.
Short cotton fibres, or linters, provide cellulose used for dynamite, sausage skins, lino, cellophane, rayon, photographic film, nail polish, moulded plastic and solid fuel rockets, and to thicken ice cream, make chewing gum chewy and allow make-up to flow smoothly.
Crushed cotton seed yields a useful vegetable oil and the meal from crushed seeds is used for cattle feed, fish bait and organic fertiliser.
- Annual: lives for a year or less.
- Capsule: dry fruit that opens by valves, slits or pores to release seeds (dehiscent) and is composed of two or more united carpels (the basic unit of the female sexual organ).
- Herb: plant with fleshy parts rather than a persistent woody stem above ground.
- Ovoid: three-dimensionally egg-shaped with broader end at base.
- Perennial: lives for at least two years.
- Subglobose: almost spherical.