Summary discussion
The interest in school gardening has grown over the past years, with some evidence that school gardening can provide children with a positive learning environment to help them improve their awareness and understanding of food and where it comes from, and possibly increase children’s willingness to consume fruit and vegetables. However, the evidence supporting these claims is based on research evaluating short-term interventions using small sample sizes. Despite the lack of funding, gardening in schools has increased in popularity, with gardening being added to the UK curricula for children in Key Stages 1–3 from September 2014.143 The current two trials have found very little evidence to support the claims that school gardening can improve children’s fruit and vegetable intake (see Chapter 5). However, all groups had increased their gardening activity over the course of the study. The RHS-led group had increased the most, but there were no statistically significant differences between groups in gardening level at follow up. This lack of difference in gardening between groups may well have influenced the primary outcome. A high level of gardening, as characterised by the RHS levels, needs to be undertaken to produce a change in intake (see Chapter 7). The RHS considers that unless a head teacher is supportive of school gardening, despite their best efforts to improve children’s knowledge and attitudes, the positive efforts will produce little or no results. School and community gardens do provide other benefits even if they do not improve children’s fruit and vegetable intake, potentially improving psychological and social well-being in children.139 Although these outcomes were not explored in the current study, it does demonstrate that, despite our findings relating to impact on diet, school gardens could be a useful educational tool.
In relation to improving children’s knowledge of and attitudes towards fruit and vegetables as a result of participating in a school gardening intervention, these two trials provide limited evidence to suggest that such an improvement takes place (see Chapter 6). For trial 1, the RHS-led gardening intervention was associated with an increase in the total number of types of vegetables recognised; however, this difference was not significant after adjustment for baseline measurement and possible confounders. A limitation of researching children’s knowledge of fruit and vegetables, or any other healthy nutrition education, is that there are very few validated tools.144 More pilot research needs to be conducted to determine the reliability and validity of children’s knowledge questionnaires, one of the fundamental components of the SCT.132
The process evaluations have provided some evidence to support previous research that school gardening can improve children’s fruit and vegetable intake (see Chapter 7). The results from this chapter have demonstrated that when gardening in schools is implemented at a high level, it can have a positive association with children’s fruit and vegetable intake. Previously successful gardening interventions suggest that future research needs to explore involving additional activities to improve children’s consumption levels.47,126 This could be through including nutritional education or cooking lessons. Parental involvement and parents’ own consumption levels have always been considered pivotal, and should be incorporated into intervention designs. The RHS states that for a school garden to be successfully established, there are certain elements that are required.145 The scheme must be supported in full by the head teacher. It is not suggesting that they need to be involved in the garden themselves; however, each school needs to identify how gardening will fit into the school day through including gardening in the school development plan. Examples of how this could be done would be ensuring that gardening is included across the curriculum, involving parents, identifying methods of linking in the community (such as through visiting a local allotment) and providing staff with the training necessary to be confident to teach gardening. Other examples are setting up a garden committee, as this will avoid pressure being placed on one teacher to maintain the garden, and helping to develop ongoing projects such as gardening clubs. Attempts need to be made to link in school gardening with the school catering company and/or staff, so that any produce grown can be included in school dinners to encourage children to taste what they have grown and be proud of their achievement. In addition, schools should attempt to use the produce from gardening in cooking lessons, to help children learn how to prepare the food themselves.56
In addition to the RHS school gardening programme run in this study, the RHS is currently developing new resources for teachers to use in the classroom, with gardening-related themes such as ‘grow your own food for your lunchbox’. The fundamental principle behind these developments is to teach gardening in the curriculum to help children develop a lifelong love of gardening, growing and their environment.56 It is should be noted that improving children’s fruit and vegetable intake is not one of the primary aims; nevertheless, the RHS hopes that educating children in gardening will in turn lead to an understanding of what they eat and where it comes from. Although gardening interventions may support small improvements in children’s knowledge of the environment, nutrition, and psychosocial and physical outcomes,53,139–142 additional intervention activities need to be integrated to produce lasting change in fruit and vegetable consumption.
Parents can help to facilitate change in their children’s fruit and vegetable intake.77 Exploring the nutrient information collected at baseline has identified a positive public health message for parents, which could improve not only their own dietary habits, but also their children’s. This is the first large survey of London children to explore this association. It found that eating a family meal together at a table had the largest effect on children’s fruit and vegetable intake. Children in families who stated that they ate together every day had 1.5 more portions of fruit and vegetables daily than those whose families reported never eating together at a table, after adjusting for possible confounders. It also found that sometimes eating at a table together increased children’s fruit and vegetable consumption by more than a portion. The importance of the family meal is supported by previous research in preschool children99 and primary school children.77,107,108 Parental intake is strongly associated with children’s intake,119,120 as was found in this study. Parents stating that they consumed fruit and vegetables more frequently was associated with higher consumption in their children.
This is the first study in the UK to identify that cutting up fruit and vegetables facilitates primary school-aged children’s intake.77 If children have access to prepared fruit and vegetables at home, they are more likely to eat them. Research has been conducted in older children supporting this finding.101,122 Future interventions could be tailored towards improving parental intake of fruit and vegetables, to facilitate children’s intake.
There are some barriers to implementing a school gardening programme. School gardens require long-term commitment if they are to be successfully established.54 It is important to have a supportive team involved in the school garden to help maintain it over the summer months when the school is closed. The length of time spent in the interventions will also affect the chances of long-term change in children’s fruit and vegetable intake. Their consumption patterns are unlikely to be affected if their involvement in the actual intervention is limited.
The dietary assessment measurement used for these trials was a 24-hour recall tick list. The strength of the CADET diary is that it uses age- and gender-specific food portion sizes to calculate food and nutrient intake. The methodology used to administer the CADET diaries in schools was improved to help ensure completeness of the data collected. Children’s intake at school was recorded in CADET by trained fieldworkers and intake at home was recorded by parents/carers. An instructional DVD was sent home for parents to watch, to help them understand how to complete the CADET diary. Also, after the school food diary collection day, the fieldworker returned to the schools to collect and check the diaries with all the children, and if necessary conduct a retrospective recall. A 1-day tick list is an economically effective way of gathering nutrient information from children; however, it may not reflect true nutrient intake in the longer term. The CADET diary does avoid the issues with child self-reported food intake, and is less of a burden on the participants than the most commonly used alternative, a weighed 4-day food diary.
All analyses were conducted using multilevel analysis, a robust statistical methodology. The benefit of this technique is that the means and CIs for the different foods and nutrients will be more accurate; as children within a school are more similar to each other in terms of their food consumption, there will be less variability within the sample compared with a random sample from the whole population.86,124 This level of analysis is rarely applied to the secondary outcomes, such as children’s knowledge and the process measures questionnaires.
Recommendations for future research
Despite the lack of evidence of a quantitative impact of school gardening on children’s intake, anecdotally, school gardening may have positive attributes.54 When a school garden is successfully integrated into the school environment, it can provide a link between the community and the school. Beyond investigating school gardening initiatives, in order to increase children’s fruit and vegetable intakes, research needs to focus on intervention designs that tackle individual intake, family intake, school environment and the wider community.54 The RHS believes that school gardening can provide vital links to members of the community who otherwise have little involvement with their child’s education,56 but this was not assessed in our study. This is supported in academic literature.60,146 In order to fully appreciate how schools could be involved in improving children’s diets, a full review of the mechanisms of change and the major constraints, and the impact of both the external and wider school environments, such as school meals and food policies, is warranted.39
Successful fruit and vegetable interventions in schools tended to have only a small impact on children’s fruit and vegetable intakes.31 School gardening interventions that have identified a change in children’s diets have additional components. A recent systematic review of school-based interventions to improve children’s inactivity and nutrition knowledge stated that, for interventions to be successful, the vital components were integrating the intervention into the school curriculum, parental involvement through homework activities and developing a whole school approach through influencing changes to school policy around nutrition and physical activity education.147,148 In Australia, a school gardening and cooking programme, the Stephanie Alexander Kitchen Garden Program, has had government support to develop the required infrastructure.149 This programme has been funded by national and state support between 2008 and 2012, with the government spending $12.8M, approximately £8.7M, over 650 schools to develop cooking and gardening facilities. The Australian government has also recently invested an additional $5.4M (approximately £3.6M) on this programme.149 The evaluation of this intervention has shown positive results for changing children’s behaviour in terms of fruit and vegetable intake, willingness to try fruit and vegetables and confidence in gardening and cooking skills. Future research into school gardening should be conducted with additional components such as cooking included, and parental involvement.
The WHO and the Food and Agriculture Organization believe that school-based interventions are a fundamental part of improving the population’s fruit and vegetable intake.150 Approaches to increase support from industry and governments, to improve access to fruit and vegetables in all the settings in which children spend time, should be explored.
Future research should also be conducted to explore the effect of community gardens on children’s fruit and vegetable intake. Currently, there is a need for a robust study design to ascertain the role community gardens play as an intervention tool to improve children’s diets. Similar to school gardening, there are other benefits of community gardening besides focusing on fruit and vegetable consumption. Again, as with school gardening, community gardens are seen as a positive place for bringing different sections of the community together, and can have positive effects on the social well-being of the people involved.151 Some community gardens have also been linked to school distribution programmes,52 while other studies have identified that community gardens can be used as a replacement for a school garden,60 with the community gardeners providing support and time to help local schools develop children’s knowledge of gardening. Schools involved with a community garden could elevate the responsibility of the school in running and maintaining the garden, which might make school gardening easier to maintain.
In addition to school-based intervention studies, there needs to be more focus on the home environment. We have identified the importance of eating together as a family to improve children’s fruit and vegetable intake.77 Future intervention studies need to focus on parental involvement in supporting positive reinforcement and rewards around fruit and vegetable consumption, such as cutting up fruit and vegetables and eating fruit and vegetables together. A recent study stated that the barriers for parents are cost, family preferences and a limited choice of fruit and vegetables in restaurants. More pilot studies are needed that attempt to improve the home environment and to develop a suitable intervention to assist parents in overcoming these issues.152
The quality of the tools used to evaluate these programmes is a further research concern. There are very few validated tools to explore nutrition knowledge in children; testing and developing these tools is essential to accurately measure children’s understanding of healthy dietary behaviour. Another limitation of measuring children’s knowledge is that, naturally, children do guess if they do not know the right answer. The design of nutrition knowledge questionnaires should always provide children with the option to write ‘don’t know’ – this could reduce the percentage of children guessing, and improve the questionnaire’s ability to accurately measure knowledge. Furthermore, knowledge questionnaires should be assessed for reliability. A possible method would be to use children’s school assessment scores and validity, through conducting a test–retest evaluation.
Conclusion
To conclude, this report has looked at the results from the first cluster RCTs designed to evaluate a school gardening intervention. The primary analysis from the two trials has found very little evidence to support the claims that school gardening alone can improve children’s fruit and vegetable intake. In both trials, the gardening levels increased across all groups and there was no statistically significant difference between the intervention and control groups in terms of improvement in gardening level from baseline to follow-up. This lack of differentiation between groups is likely to have influenced the primary outcome. However, process measures evaluation found that when the gardening intervention was implemented at the highest intensities within the schools, there was a suggestion that it could improve children’s fruit and vegetable intake by a portion. Improving children’s fruit and vegetable intake remains a challenging task. This study highlights the need for more sophisticated and accurate tools to evaluate diet in children. Future intervention designs should include a greater level of parental involvement in school interventions, along with related components such as cooking, to substantially improve children’s fruit and vegetable intake. In addition, the home environment has been demonstrated to be an important focus for intervention.
