Judahites knew that Sodom and Gomorrah had become a land of nettles and salt pits. There were many salt pits along the southern coast of the Dead Sea (Deuteronomy 29:23). The only thing productive about the area was to dig pits around the sea allowing the water to fill the pits. After evaporation salt could be gathered from the pits.
1 This is still the case today; the area around the Dead Sea is still a wasteland.
9 Therefore, as I live,” declares the LORD of hosts, the God of Israel, “Moab shall become like Sodom, and the Ammonites like Gomorrah, a land possessed by nettles and salt pits, and a waste forever. The remnant of my people shall plunder them, and the survivors of my nation shall possess them.”