Colored Cotton, Without Dyes

While colored cotton remains largely unknown, it has existed for thousands of years, and is grown worldwide. It grows in earthy shades of red, green, and brown, eliminating the need for dyes.

Growing colored cotton began around 2700 B.C., in Indo-Pakistan, Egypt, and Peru. It grew in natural colors - mocha, tan, gray and red-brown - and was prized by the hand-spinner. With the industrial revolution and its newly invented looms, short-fibered colored cotton was displaced by longer-fibered white cotton. As the white variety grew in popularity, colored cotton nearly disappeared, kept alive only by the hand-spinners.

Colored cotton's commercial use was limited until recently. Originally the fibers were too short to machine spin. But in 1982 a California breeder began a breeding and selection program toimprove the length and quality of the fiber. By 1988 the fibers were long enough to machine-spin successfully. While genetic improvements have made it possible to spin the colored cotton on ordinary machines, they are still typically blended with white cotton. This improves yarn strength and reduces cost, but also reduces color intensity.

Naturally colored cottons are unique because they don't require dyeing in the fabric manufacturing process. In traditional processing, cotton fibers are bleached, then colored with dyes that often contain heavy metals. The processes produce significant amounts of contaminated waste water. Processing naturally colored cotton uses less water and energy.

Growing colored cotton can be a risky business, but the rewards can be high. For example, white cotton produces 2 to 2-1/2 bales per acres, and come colored cottons yield barely half that much. But colored cotton can sell for three to four times as much as white. Colored cotton plants also resist pests and drought better, so they are very adaptable to dryland farming. Currently, most commercial production of naturally-colored cotton is in Texas and Arizona.

U.S. Department of Agriculture scientists are working to develop superior naturally colored cotton yarns and fabrics. They are comparing the properties of common yarns with the first yarns produced from naturally colored cottons using an ARS-patented method known as staple-core spinning. The experimental yarns contain high tenacity poylester on the inside and naturally colored cotton on the outside. The bicomponent yarns look and feel like colored cotton but are stronger and more serviceable than yarns spun from the fibers on conventional machines. Cotton producers, the textile industry, and consumers all have something to gain from the commercialization of the staple-core method for use with naturally colored cottons.

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