The main objective of this study was to determine the effects of a vocational horticulture program on the self-development of female inmates in a federal prison camp (FPC) in Bryan, Texas. Subjects were sampled from the inmate population of FPC-Bryan and assigned to two groups. Group A was comprised of 36 inmates participating in the Master Gardener program and Group B, the control group, was comprised of 26 inmates who were not participants in the Master Gardener program. A confidential 55-item survey was administered in a pretest-posttest fashion and contained questions from Rotter's (1966) Internal-External Control of Reinforcement Scale and the Multidimensional IE Scale (Gurin et al., 1969), Pugh's (1992) Prison Locus of Control Scale, the Rosenberg Self-Esteem Scale (Rosenberg, 1965), and the Satisfaction With Life Scale (Diener et al., 1985). No significant differences were found between the pre- or post-tests of the Master Gardener and control groups. In addition, no significant differences were found for generalized internal-external locus of control and situation specific internal-external locus of control when pretest and posttest mean scores were compared within each group. However, Master Gardener and control participants significantly increased their self-esteem and global life satisfaction scores between the pre- and post-tests. Due to the high occurrence of research subjects reporting a history of drug or alcohol abuse, the pre- and posttest mean scores of drug or alcohol abusers and nonabusers participating in the Master Gardener program were compared. No significant differences as a result of participation in the Master Gardener program were found for nonabusers for all variables tested and for generalized internal-external locus of control and global self-esteem for drug or alcohol abusers. Substance abusers did significantly increase their situation specific internal-external locus of control and their global life satisfaction while participating in the Master Gardener program.