Abstract: A spraying apparatus, which sprays herbicides, fungicides and insecticides mixed in water or liquid fertilizer, includes a fluid storage tank, a pump and one or more spray heads. An agitator, which is mounted in the fluid storage tank on the end of a bypass return pipe extending between the pump and the fluid storage tank, mixes the fluid in the fluid storage tank. The agitator includes a conical plate or cap overlaying the opening in the bypass return pipe. Spiral shaped fins or ribs are mounted on the concave side of the conical plate for directing the fluid from the bypass return pipe in a spiral rotating fashion to thereby mix the fluid in the fluid storage tank by imparting a gentle rolling action to the fluid. A nozzle between the bypass return pipe and the conical plate provides a fixed gap to control the fluid momentum in the fluid storage tank. The spraying apparatus also includes an anti-vortex device mounted on a fluid outlet pipe.