How cotton is grown and harvested

Cotton is almost pure cellulose, and one machine invention in 1793 made it cheap enough to clothe the world.

stations: 3
things downstream: 27

The short version

Cotton is a shrub grown in long frost-free seasons with plenty of sun. The fiber grows inside a protective case called a boll, around the seeds. When the bolls open, a picker machine lifts the fiber out, or a stripper tears the whole boll off the plant after a defoliant or a freeze has dropped the leaves.

Plant in a frost-free field

Cotton needs a long stretch without frost, lots of sunshine and moderate rainfall, usually 50 to 100 cm a year. Heavy soils suit it, and much of today's crop is irrigated in drier regions. Bt varieties carry a bacterial gene that kills bollworms.

50 to 100 cm of rain
Drop the leaves

In the tropics cotton is a perennial and keeps growing. Farmers spray a chemical defoliant, or wait for a freeze, so the leaves fall and the bolls can be taken cleanly.
Pick or strip the bolls

A cotton picker removes the fiber from each boll without harming the plant. A stripper pulls the entire boll off, and is used where wind makes picker varieties hard to grow. In some developing countries the crop is still picked by hand.

End of the lineRaw cotton Next it goes into nail polish, tampon, cotton swab and 2 more.

Worth repeating

Hand-roller gins were already used in India in the 6th century, long before Eli Whitney's 1793 machine.
In January 2019 a cotton seed sprouted on the far side of the Moon inside China's Chang'e 4 lander.
Before the cotton gin, producing one bale of cotton took over 600 hours of human labor.