Painting Rebar for Plant Supports. http://Rebarp.notlong.com 27 March 2007. Eight foot rebar painted to inhibit rust with Tremclad for use as supports for the tomato cages, and to tie the top part of the tomatoe plants. This coating will last for about 7 years, judging from past experiences. This is a cheap and effective way to support tomato plants. The rebar rusts quickly unless painted. Durgan.