School gardening increases knowledge of primary school children on edible plants and preference for vegetables.

At least 10% of children worldwide are diagnosed with overweight. Part of this problem is attributed to low vegetable intake, for which preference at a younger age is an indicator. Few studies examined long-term effects of school garden interventions on the knowledge about and preference for vegetables. Therefore, in this study, an intervention period of 7 months (17 lessons) was organized for primary school students ( = 150) of age 10-12 years in the Municipality of Nijmegen (the Netherlands). Surveys were conducted before and after the intervention period to test the ability of students to identify vegetables, to measure their self-reported preference for vegetables, and to analyze students' attitudes toward statements about gardening, cooking, and outdoor activity. The long-term effects were measured by repeating the survey 1 year after the intervention ( = 52). Results were compared with a control group of students ( = 65) with similar background and tested for significance with  = 0.05. School gardening significantly increases the knowledge of primary schoolchildren on 10 vegetables as well as their ability to self-report preference for the vegetables. The short-term ( = 106) and long-term ( = 52) preference for vegetables increased ( < 0.05) in comparison with the control group. The latter did not show a significant learning effect ( > 0.05). This implies that the exposure to vegetables generated by school gardening programs may increase willingness to taste and daily intake of vegetables on the long term. Students' attitudes toward gardening, cooking, and outdoor activity were unaffected by the intervention.