Effect and process evaluation of a real-world school garden program on vegetable consumption and its determinants in primary schoolchildren

OBJECTIVES: This study aimed to investigate the effectiveness of a school garden program on children’s vegetable consumption and determinants and to gain insight into the process of the program. METHODS: The “Taste Garden” is a real-world nine-week school garden program developed and implemented by a local organization. A total of 350 children (149 intervention group, 201 control group) filled out questionnaires on vegetable consumption, determinants and process of the program. Additionally, teachers filled out a process evaluation questionnaire. For effect evaluation, interaction effects (time x group) were considered, using multilevel repeated measures analyses in MLwiN 3.02. Interaction effects were repeated, taking into account quality of implementation (time x implementation group). Process evaluation was descriptively assessed with SPSS 24.0. RESULTS: Overall, beside some practical concerns of teachers, the program was well perceived by teachers and children. However, an intervention effect of “The Taste Garden” was only found for knowledge (p = 0.02), with a very small effect size (0.55%). When taking into account implementation quality, only small effects were found for awareness (p between 0.005 and 0.007 and an effect size of 0.63%) and knowledge (p between 0.04 and 0.09 and an effect size of 0.65%). CCONCLUSIONS: Evaluation of the real-world “Taste Garden” program, which was positively perceived by teachers, showed no effects on vegetable consumption and small effects on its determinants. Adaptations of the current format and longer follow-up periods are therefore recommended.