There was almost no soil left on earth, the visitors to earth had seen to that. Jem had seen them land, and narrowly escaped their transformation of earth’s atmosphere.
It was strange the things that people had brought into the underground shelter when they fled from the poisonous blue gas. When George said that he would bring a comfort station no one expected him to arrive carrying a loo, for there was no spare water.
So the loo had become a throne to mankinds survival. It contained a small amount of soil, which was now being replicated, food then flowers.
Jakes is an old English word for the Privy.