Research identified and described the motivational orientations of the participants in the horticultural certificate programs at Longwood Gardens in Pennsylvania. Questionnaires were distributed to paying participants attending the certificate programs in fall 1994. The first part of the questionnaire included the Education Participation Scale (EPS), which assessed the influence of six motivational orientation factors and compared the influence of these factors between participant groups. The questionnaire included demographic questions and assessed the influence of other reasons not included in the EPS. Data analysis included frequency determination, a t-test, and an analysis of variance. Findings indicated that participants attending the certificate programs tended to be women, older, and Caucasian and to have higher levels of socioeconomic status than adult education participants in general. Cognitive interest and professional advancement had the greatest influence of all EPS factors for those participating in the programs. It also appeared that a leisure goal-oriented motivational domain, related to the participants' desire to improve in their home gardening activities, had great influence on the participants' decision to participate. Comparison of the EPS factor scores of participant groups indicated differences between them primarily in professional advancement, external expectations, and cognitive interest. (YLB)