The goal of this research project was to determine if introducing intergenerational interactions would supplement or detract from the use of horticulture as a therapeutic tool when working with elderly adults and preschool children. The program was set up to compare independent group activities with intergenerational activities. A group of elderly adults in the University Adult Day Service and a group of preschool children in the University Child Development Laboratory School took part in both separate age group and intergenerational activities. There were three sessions each week: one for the children's group, a second one for the elderly adults' group, and a third one that combined both groups. The same activity was done during all three sessions each week, with modifications to make the activity appropriate for each age group and to make it more interactive for the intergenerational group. These activities took place in the campus building where the day care centers are located. Four volunteers assisted with the activities. Two worked with the children's group both during separate and intergenerational activities, and two volunteers similarly assisted with the elderly adult group. Video cameras were used to record each session. These videos were viewed and evaluated after the 10-week horticulture therapy program was completed to score attendance and participation during separate age group activities, and attendance, participation, and interaction between the two groups during intergenerational activities. This data was used to determine if introducing intergenerational interactions affected the individual's attendance or participation, and to determine if the interactions between the two groups showed any change over time.

Several variables were shown to affect the outcome of research. The first variable discussed is the effect of the staff, volunteers, or administration on the participants and the activities. Staff and volunteers can greatly affect intergenerational interactions by: 1) failing to encourage participation from participants of all ages, 2) lacking experience or having discomfort in working with special populations, 3) failure to establish adequate communication with the researcher or with each other, or 4) demonstrating a negative attitude towards the project. The second variable in research is the limitation introduced by data analysis using video. While video recording is useful in evaluating data, it can cause problems due to a limited viewing area, limited viewing angles, blocked screens, or unfamiliarity with recording equipment.

Videos were used to assess participation and interaction. Participation scores include three categories: "no participation" for present but inactive participation, and "working with direct assistance" or "independent participation" for active participation. Participation was affected by the horticulture activities' set up, difficulty level, and availability of assistance from volunteers. Children's participation during separate group activities was affected mainly by the difficulty level and set up of activities. Elderly adult's participation during separate age group activities was affected mainly by each individual's abilities and availability of assistance. Children's intergenerational participation scores show an increase in the category of "working with direct assistance", while elderly adults' intergenerational scores show an increase in the categories of "no participation" and "independent participation". In part, the change in intergenerational participation was due to a decrease in the assistance available from volunteers for each individual.

Lastly, the percentage of total interaction time between the generations during activities increased over time. However, the introduction of intergenerational interactions detracted from the use of horticulture as a therapeutic tool for elderly adults and preschool children. It is recommended that intergenerational programming may not be useful to fulfill specific horticulture therapy goals for these groups. At the same time, the intergenerational activities involving horticulture plant-based activities were more successful at increasing interactions than the craft-type activities. Therefore horticulture may be a useful activity for intergenerational programs with a goal of increased interaction and relationship development.