Randomisation and masking
We used a pseudo-random-number generator (sample function, R studio) with a random seed to choose participant assignments. Participants were randomly assigned (1:1) independently within each community garden waiting list to either the community gardening group (intervention group) or to stay on the waiting list with no gardening (control group). The approach involved permuted block randomisation with varying block sizes. Given the size of each garden waiting list, the algorithm randomly selected blocks of size two, four, or six, so that the total number of participants in all blocks was equal to the number of people on the waiting list for the garden. Assignments were generated by study statisticians (DHG and KKH) who had no contact with participants. Randomised assignments were transmitted to the study coordinator in sealed envelopes. The study coordinator informed participants of their group allocation after baseline data collection. Participants randomly assigned to the control group were not eligible to be re-randomised in a subsequent year. Study participants were not masked to assignment, but study staff conducting assessments, investigators, and statisticians were masked to participant assignments until after data collection was completed and the planned analyses for primary outcomes were finished.