A fertilizing device for installing in a water system comprising a first half housing removably attached to a second half housing; an intake pipe disposed on a first side and an outlet pipe disposed on a second side of the first half housing, the intake pipe and outlet pipe are both fluidly connected to the inner cavity of the first half housing; a box with apertures disposed in the first and second half housings for holding a chemical bar with fertilizer; wherein the intake pipe is connected to a first portion of a pipe of the water system, the outlet pipe is connected to a second portion of the pipe of the water system; wherein water from the water system can enter the intake pipe, mix with the chemical bar, and exit via the outlet pipe.