In places across the South, it is customary to paint a porch ceiling blue. This tradition began in the Low Country of South Carolina, and is frequently seen in Beaufort and Charleston. It's a pretty color, but there's a reason people incorporated blue in their homes- as protection from evil spirits.
This “haint blue,” first derived from the dye produced on Lowcountry indigo plantations, was originally used by enslaved Africans, and later by the Gullah Geechee, to combat “haints” and “boo hags”—evil spirits who escaped their human forms at night to paralyze, injure, ride (the way a person might ride a horse), or even kill innocent victims. The color was said to trick haints into believing that they’ve stumbled into water (which they cannot cross) or sky (which will lead them farther from the victims they seek). Blue glass bottles were also hung in trees to trap the malevolent marauders.
While “haint blue” has taken on a life of its own outside the Gullah Geechee tradition—it’s currently sold by major paint companies like Sherwin-Williams, and marketed to well-to-do Southerners as a pretty color for a proper porch ceiling—the significance of the color to the descendents of the Lowcountry’s enslaved people still remains.
Indigo was grown in South Carolina by enslaved workers before the Revolutionary War. It was a lucrative trade, but not for those who brought the skill to raise and extract the dye, along with their spiritual beliefs, with them when they were taken from West Africa. While artificial dyes are used almost exclusively now, the Gullah Geechee community is seeking to bring back the indigo plant along with the history behind it. Read about haint blue and the people who produced it at Atlas Obscura.