Why was the demand for slavery higher in the Deep South?

today as describing the plantation economy of the slavery states in the Deep South, which led to the creation of "the second Middle Passage." But it is important to understand that this was not simply a Southern phenomenon. Cotton was one of the world’s first luxury commodities, after sugar and tobacco, and was also the commodity whose production most dramatically turned millions of black human beings in the United States themselves into commodities. Cotton became the first mass consumer commodity.