VTA is an umbrella concept which includes psychological symptoms, tension and distress; the RTA concept includes behavioral controls and positive self-esteem. Subjects were 33 incarcerated offenders (8 female, 25 male) with significant substance abuse history who completed pre- and post-test administrations. As expected, post-test scores showed significant decreases in the VTA measures. However, significant increases in the RTA measures, which were also expected, did not occur. Results suggest that a prison horticultural therapy (HT) program, which tries to show offenders the connection between growing plant life chemical-free and keeping their bodies chemical-free, may benefit substance abusing offenders. Some HT participants who had not profited from verbal therapy alone, due to introversion or suspiciousness, became more open to verbal sessions when conversations were centered around plant propagation and organic gardening. Tables, references