A pop-up sprinkler unit for mounting beneath the surface of a soil formation includes an outer cylindrical housing for subsurface mounting with an inner housing carrying a nozzle and drive turbine with a protective sleeve of a grit resistant material reciprocably mounted between the inner and outer housings for extending with the inner housing up through a portion of the soil and includes a grit deflector on the housing surrounding the sleeve for deflecting grit from between the sleeve and housing when the inner housing and sleeve is retracted.