Forty-eight county jail inmates, matched by sex and race, were randomly assigned to the Garden Project or other New Generation Jail programs. The TCU Self-Rating Form was administered to subjects at baseline prior to assignment, at discharge from the jail, and 3 months post-release. Changes in psychosocial functioning while in treatment and post-release were examined within the context of inner-city social ecology. The majority of San Francisco county jail inmates are incarcerated for substance abuse related charges. The reduction in the number of types of drugs used post-release was greater in subjects who were in the Garden Project, suggesting that horticultural therapy may be a particularly relevant jail treatment intervention for that population. The article examines horticultural therapy's clinical relevance in cultivating healthy self development in light of the psychological theories of Heinz Kohut and Carl Jung. Figures, references, notes