Home cannabis cultivation in the United States and differences by state-level policy, 2019-2020

Background: As of 2022, all but two U.S. states with adult-use cannabis laws also allow home cultivation. Home cultivation has the potential to support or oppose public health measures, and research in U.S. states is nascent. Objectives: 1) estimate the percentage of respondents who reported growing cannabis plants; 2) estimate the average number of plants grown; 3) examine the association between home cultivation, jurisdiction, and individual-level factors; and 4) examine the association between home cultivation and state-level policies in adult-use states. Methods: Repeat cross-sectional survey data come from U.S. respondents aged 21-65 in 2019 and 2020. Respondents were recruited through online commercial panels. Home cultivation rates were estimated among all U.S. respondents (n = 51,503; 46-52% male). Additional analyses were conducted on a sub-sample of respondents in states that allowed adult-use home cultivation (n = 29,100; 50% male). Results: A total of 6.8% and 7.3% of U.S. respondents reported home cultivation in 2019 and 2020, respectively. Respondents in states that allowed adult-use home cultivation had higher odds of reporting home cultivation than respondents in states without medical or adult-use cannabis laws (AOR = 1.48, 95% 1.26, 1.75). Among respondents in states that allowed adult-use home cultivation, the median number of plants that respondents reported growing was below state cultivation limits. Conclusion: Home cultivation rates in the U.S. were higher in states that allowed adult-use home cultivation; however, other evidence suggests these same states had higher rates predating adult-use legalization. Further work is needed to examine how home cultivation relates to public health measures in adult-use states.