Cotton thread is produced out of the white lint, or fibers surrounding the cotton seeds. It grows best in a hot, humid climate, therefore the American South was perfect for cotton growing. Cotton was the most widespread plant in the Southern plantation agriculture before the Civil War, because the British textile industry had a huge demand for American cotton. Most of the Deep South ― from South Carolina and Georgia to the lower Mississippi valley and Louisiana ― based its economy almost entirely on cotton growing and exporting. Since most of the manual labor was done by black slaves, cotton was a major reason why Southerners refused to give up slavery as an institution.Today, cotton is far less significant economically, but it is still grown in large areas in the South.