NON-METALLIC PLANT SUPPORT SYSTEMS, NAMELY NON-METALLIC PLANT BRACKETS, NON-METALLIC PLANT RINGS, NON-METALLIC HOLDERS TO SUPPORT PLANT STALKS, NON-METALLIC PLANT BRACKETS WITH NON-METALLIC PROTECTIVE CAPS, NON-METALLIC PROTECTIVE CAPS OR DOMES FOR USE WITH NON-METALLIC PLANT SUPPORT BRACKETS