Evaluation of the impact of school gardening interventions on children's knowledge of and attitudes towards fruit and vegetables. A cluster randomised controlled trial

•A school gardening intervention led by RHS specialists was compared to teacher-led.•Intervention impact on knowledge and attitudes to fruit and vegetables was compared.•There was little evidence of consistent differences between the two interventions.•Children recognised more fruit and vegetables in the RHS-led gardening intervention.•Children reported eating more fruit and trying new fruit in the teacher-led group. Involvement of children in gardening has the potential to increase liking of fruit and vegetables (FV) and consequently, intake, but research results are mixed. School gardening led by external specialists such as the Royal Horticultural Society (RHS) could have more impact than teacher-led gardening on children's knowledge of, and attitudes towards, FV. Data from a cluster randomised controlled trial were used to compare a RHS-led school gardening intervention with a teacher-led gardening intervention amongst 7–10 year olds in 21 London schools. A short questionnaire was developed and used to identify children's knowledge and attitudes towards FV consumption before the garden intervention and 18 months afterwards. Results from multilevel regression models, both unadjusted and adjusted for baseline responses and socio-demographic factors, were reported. Attitudes to FV intake were compared between groups. Change in FV knowledge was used to predict change in FV consumption assessed using 24-hour food diaries. In comparison with the RHS-led group (n = 373), teacher-led children (n = 404) were more likely to agree they ate lots of fruit (p