BackgroundGarden-based interventions show promise for improving not only child nutrition, but other indicators of child health. Yet, existing systematic reviews of garden-based interventions often focus on one particular health outcome or setting, creating a need to holistically summarize review-level evidence on the role of garden-based interventions in early childhood. To fill this gap, we performed an umbrella review of garden-based interventions to examine their role in early childhood health promotion for children ages 6 years and younger, examining effective components of garden-based interventions and critically evaluating existing evidence.MethodsWe searched the following databases: PubMed, PubMed, PsycINFO, ERIC, CINAHL, Embase, Scopus, OVID-Agricola, and CAB Direct, limiting to reviews published from 1990 to August 2019. Of the 9457 references identified, we included a total of 16 unique reviews for analysis.ResultsAcross reviews, garden based-interventions were most effective at improving nutrition-related outcomes for children, including nutritional status and fruit and vegetable consumption. Few reviews examined child health outcomes of garden-based interventions that were not nutrition related, such as physical activity, or academic performance. Across settings, there was the most evidence in support of garden-based interventions conducted in home gardens, compared to evidence from early care and education or community settings. We were unable to report on most effective components of garden-based interventions due to limitations of included reviews.ConclusionsExisting evidence is difficult to interpret due to methodological limitations at both the review and primary study level. Therefore, the lack of evidence for certain child health outcomes should not necessarily be interpreted as an absence of an effect of garden-based interventions for specific outcomes, but as a product of these limitations. Given the breadth of evidence for garden-based interventions to improve a number of dimensions of health with older children and adult populations, we highlight areas of future research to address evidence gaps identified in this umbrella review. Further research on the role of garden-based interventions, including their impact on non-nutrition early childhood health outcomes and how effectiveness differs by setting type is necessary to fully understand their role in early childhood health promotion.PROSPERO registrationCRD42019106848.