A kit for retrofitting a grass trimming apparatus with a spinning support guide includes a base mount disc, a semispherical base, a guide fastener having a head with a hexagonal opening, one or more spacer discs, one or more disc fasteners, and a hex key. Furthermore, the base mount disc is adapted to affix to the semispherical base with the one or more disc fasteners and define a chamber for partially housing the guide fastener therein, and the hex key is adapted to rotate the guide fastener to threadably attach to a threaded receptacle on an underside of the grass trimming apparatus.