The Dark History of Indigo, Slavery's Other Cash Crop

A vat of indigo blue dye in the process of production. Indigo was one of the first plants the British attempted to grow when they arrived in North America. Wikimedia Commons (CC By 3.0)

There was a time, not all that long ago, that if you wanted your toga or whatever to be a different color, you'd have to go find something in nature to dye it with: maybe mud, maybe an insect, or the seed, flower, root or leaves of a plant.


Color Before Chemistry

Before 1856, when a teenaged British chemist named William Perkins accidentally formulated the first synthetic dye while trying to find a cure for malaria (he produced mauveine, which was an intense purple color), harvesting natural resources for dyes was a big deal.

"Until Perkins' discovery, anything that had color — clothes, shoes, rugs, tapestries — was dyed with either a plant, a bug or a mineral," says Donna Hardy, the president and founder of the International Center for Indigo Culture.


Perkins discovered the means of making purple cheaply and in large quantities — before that, purple dye was very precious; the most reliable source was to extract it from the dessicated mucus gland of a sea snail. Blue was easier to come by, and useful because it could be mixed with other colors to make purples and greens, but before the advent of synthetic dyes, getting pigment out of the land was laborious.

To make anything blue, you needed indigo, an organic compound found in the leaves of certain plants — most notably indigo plants in the genus Indigofera (from India or South America), although other plants such as woad (Isatis tinctoria) contain indigo compounds, too — just in much lower concentrations. The first Indigofera used by Europeans was grown in the Far East (the word indigo comes from the Greek word for India). Indigo was highly valued in the West, but Europeans wanted their own source of indigo that wasn't so expensive. That's where the New World came in.


Indigo in North America

Until indigo dye was synthesized in Europe in 1882, a species of Asian Indigofera was a huge cash crop wherever it could be grown.

"In the 1600s, Europeans colonized North America, and immediately started trying to grow crops of economic importance," says Hardy. "Indigo is one of the first plants the British attempted to grow when they got to North America. They tried growing it in Jamestown, the Dutch tried it in New Amsterdam — present-day New York City. The French had some success in Louisiana, but nobody had much luck until Eliza Lucas came along."


In the 1730s, 16-year-old Eliza Lucas, whose father was lieutenant governor of Antigua and who had an interest in botany, was put in charge of three of her father's South Carolina plantations. She and her father had no idea what to grow there, but he sent her seeds from Antigua, and indigo seemed to Eliza to have the most promise. She married a man named Charles Pinkney who wrote down the instructions for how to grow and process indigo, and after a while they made enough seed to hand out to the neighbors, which started an indigo bonanza in the Southern colonies.

Indigo and Slavery

"Before indigo, rice and deer hides were the main exports from Charleston," says Hardy. "Native American slaves were the first export."

Of course, Eliza and Charles Pinkney didn't figure out how to grow and process indigo — their slaves did. The import of African slaves began to ramp up in the southern colonies as a result of the indigo boom in the mid-18th century. In fact, one of the biggest indigo promoters of the time, Moses Lindo, who went to Charleston from England to act as inspector general of indigo coming out of the Port of Charleston, owned a slave ship called the Lindo Packet, with which he imported enslaved people from Barbados to Charleston. And the indigo fever and the dependence on slave labor that came with it didn't end in South Carolina.


"Slavery wasn't even legal in Georgia until indigo became the main export in South Carolina," says Hardy. "The [British] governors in Georgia decided to legalize slavery to keep the indigo industry going."

Georgia's ban on slavery ended in 1751, and by the beginning of the Revolutionary War 15 years later, the enslaved population of that state had grown to over 18,000. Though the American colonies winning their independence from Britain tanked the indigo market, it was quickly replaced by rice and cotton. For its part, England turned its attention to India for its indigo needs, where British colonists forced sharecroppers to grow indigo for hardly any money. The legacy of slavery followed indigo around until it was replaced by synthetic indigo in the early 20th century, when it slipped into obscurity.


Is Indigo the Future of Sustainable Clothing?

These days, indigo dying is considered a curious historic oddity, but, according to Hardy, indigo has the potential to be part of the solution for the broken garment industry.

"The chemical formula for natural and synthetic indigo are the same, but the synthetic dye has stuff like formaldehyde in it, and synthetic dyes are all petroleum based," says Hardy. "The way we manufacture and dye clothes isn't good for people or the environment. And slavery is still a thing in the garment industry."