A web-based survey that masked participants’ identity was determined to be the most suitable approach given that in-person interviews were limited by legal restrictions on UC researchers visiting cannabis farms, and mail or telephone surveys were constrained by the lack of any readily available mailing address or telephone contact information for most cannabis growers, who are understandably discrete with this information.Survey questions focused on operational features , pest and water management, labor, farm revenue and grower demographics.Two draft surveys were reviewed by a subset of cannabis growers to improve the relevance of the questions and terminology.A consistent critique was that the survey was too long and asked for too much detail, taking up to 2 hours to complete, and that such a large time commitment would significantly reduce the response.We therefore made the survey more concise by eliminating or rephrasing many detailed questions across various aspects of cannabis production.The final survey included 37 questions: 12 opened and 25 structured.Structured questions presented either a list of answer choices or a text box to fill in with a number.Open-ended questions had a text entry box with no character limit.Condensing the survey to capture more respondents resulted in less detailed data, but the overall nature of the survey remained the same — a survey to broadly characterize multiple aspects of cannabis production in California.Data from the survey has supported and contextualized research by other scientists on specific aspects of cannabis production, such as water use , permitting , law enforcement , testing requirements , crop prices and perceptions of cannabis cultivation in the broader community.Recruitment of survey participants leveraged networks of California cannabis growers who had organized themselves for various economic and political purposes.These were a combination of county,mobile vertical rack regional and large statewide organizations, with many growers affiliating with multiple groups.
We identified the organizations through online searches and social media and sent recruitment emails to their membership list-serves.The emails contained an explanation of the survey goals, a link to the survey website and a message from the grower organization that endorsed the survey and encouraged members to participate.The emails were sent in July 2018 to approximately 17,500 email addresses, although not all members of these organizations necessarily cultivated cannabis, and the organizations noted that their mailing lists somewhat overlapped the lists of other groups that we contacted.For these reasons, the survey population was certainly less than 17,500 individual cannabis growers, but because we were not able to view mailing lists nor contact growers directly, and because there are no comprehensive surveys of the number of cannabis farms in California, we could not calculate a response rate or evaluate the representativeness of the sample.Respondents were given until Aug.15, 2018, to complete the survey.All survey participants remained anonymous, and response data did not include any specific participant identifiers.Our survey, although of limited sample size, is the first known survey of California cannabis growers and provided insights into common forms of cultivation, pest and disease management, water use and labor practices.Since completing this survey, we have discussed and/or presented the survey results with representatives from multiple cannabis grower organizations, and they confirmed that the data were generally in line with production trends.Evident in the survey results, however, was the need for more data on grower cultivation practices before best management practices or natural resource stewardship goals can be developed.All growers monitored crop health, and many reported using a preventative management strategy, but we have no information on treatment thresholds used or the efficacy of particular sprays on cannabis crops.Likewise, the details of species-level pest and disease identification, natural enemy augmentation and sanitation efforts remain unclear.
Growers did not report using synthetic pesticides, which contrasts with findings from previous studies that documented a wide range of synthetic pesticide residues on cannabis.Product selection for cannabis is very limited due to a mixed regulatory environment that currently does not allow for the registration of any insecticide or fungicide for use specifically on cannabis , although growers are allowed to use products that are exempt from residue tolerance requirements, exempt from registration requirements or registered for a use that is broad enough to include cannabis.As such, it may be that in the absence of legally available chemical controls growers were choosing allowable, biologically derived products or alternative strategies such as natural enemy augmentation and sanitation.Our survey population was perhaps biased toward non-chemical pest management — the organizations we contacted for participant recruitment included some that were formed to share and promote sustainability practices.Or, it may be that respondents were reluctant to report using synthetic chemicals or products not licensed for cannabis plants.The only other published data on water application rates for cannabis cultivation in California we are aware of is from Bauer et al., who used estimates for Humboldt County of 6 gallons per day per plant for outdoor cultivation over the growing season.Grower reported estimates of cannabis water use in this survey were similar to this rate in the peak growing season , but was otherwise lower.Due to the small sample size, we cannot say that groundwater is the primary water source for most cannabis growers in California or that few use surface water diversions.However, Dillis et al.found similar results on groundwater being a major water source for cannabis growers, at least in northwest California.If the irrigation practices reported in our survey represent patterns in California cannabis cultivation, best management practices would be helpful in limiting impacts to freshwater organisms and ecosystems.For example, where groundwater pumping has timely and proximate impacts to surface waters, limiting dry season groundwater extraction by storing groundwater or surface water in the wet season may be beneficial , though this will likely require increases in storage capacity.
The recently adopted Cannabis Cultivation Policy requires a mandatory dry season forbearance period for surface water diversions, though not for groundwater pumping.Our survey results indicate that the practical constraints on adding storage may be a significant barrier for compliance with mandatory forbearance periods for many growers.More in-depth research with growers and workers is needed to explore the characteristics of the cannabis labor force and the trajectory of the cannabis labor market, especially in light of legalization.Several growers commented on experiencing labor shortages, a notable finding given that recent market analyses of the cannabis industry suggest that labor compliance costs are the most significant of all of the direct regulatory costs for growers.Higher rates of licensing compliance among medium and large farms is not surprising given the likelihood that they are better able to pay permitting costs.Yet, that the majority of respondents indicated they had not applied for a license to grow cannabis, with over half noting some income from cannabis sales, indicates potentially significant effects if these growers remain excluded from the legalization process.More research is needed to understand the socioeconomic impacts of legalization, which likely extend beyond those accounted for in the state’s economic impact analysis, which primarily focuses on economic contributions that a legalized market will bring to the state.Bodwitch et al.report that surveyed growers characterized legalization as a process that has excluded small farmers, altered local economies and given rise to illicit markets.The environmental impacts of cannabis production have received attention because of expansion into remote areas near sensitive natural habitats.The negative impacts are likely not because cannabis production is inherently detrimental to the environment, but rather due to siting decisions and cultivation practices.In the absence of regulation and best management practices based on research, it is no surprise that there have been instances of negative impacts on the environment.At the same time, many growers appear to have adopted an environmentally proactive approach to production and created networks to share and promote best management practices.Organizations that we approached to recruit survey participants had a fairly large base membership , which is on a par with other major commodity groups, like the Almond Board of California and California Association of Wine grape Growers.Membership included cannabis growers, distributors and processors as well as interested members of the public, and some people were members of more than one organization, suggesting a large, engaged community.Most of the organizations we contacted enthusiastically agreed to help us recruit growers for our survey, and we received excellent feedback on our initial survey questions.Growers who completed the survey were also clearly knowledgeable about cannabis cultivation.Some potential future research topics include the development of pest and disease monitoring programs; quantifying economic treatment thresholds; evaluating the efficacy of different biological, cultural and chemical controls; developing strategies to improve water use and irrigation efficiency; understanding grower motivations for regulatory compliance; understanding the impacts of regulation; and characterizing the competition between labor in cannabis and other agricultural crops — to name just a few.
As cannabis research and extension programs are developed, it will be critical to ensure that future surveys capture a representative sample of cannabis growers operating inside and outside the legal market,vertical grow rack to identify additional areas for research and develop best practices for the various cultivation settings in which California cannabis is grown.Approximately, 35% of high school seniors and young adults ages 19–28 reported using cannabis in the past year.Cannabis use during youth has been a recent focus in public health research, as it may influence one’s risk for reporting symptoms of anxiety and depression.A potential mechanism underlying cannabis’ influence on mood and affective symptoms may involve frontolimbic functioning.Understanding differences in frontolimbic connectivity among young adults with frequent cannabis use may provide insight into the etiology of associated mood or affective risk.Cannabinoids in cannabis, such as 1 9-tetrahydrocanabidiol and cannabidiol , are chemicals that mimic endogenous neurotransmitters anandamide and 2AG by binding to endocannabinoid receptors CB1 and CB2.THC is the main psychoactive component of cannabis and is responsible for the subjective “high” individuals experience.CB1 activity modulates the release of the neurotransmitters GABA and glutatmate.The eCB system modulates several functions related to physical and mental health, including regulation of emotional and stress responses.More specifically, the eCB system plays a role in mood and affect , integrating reward feedback , and threat related signals.Brain regions primarily involved in the affective processing system include several interacting cortical and subcortical regions.This system is highly innervated with CB1 receptors and animal models demonstrate developmental changes in CB1 expression within the mPFC, ACC and insula , suggesting the system demonstrates plasticity during adolescence.Therefore, repeated THC exposure during development may impact naturally occurring changes in eCB functioning within mesocorticolimbic regions.Indeed, daily cannabis users have shown decreased CB1 receptor density within frontolimbic regions , ACC, and insula compared to non-users which recovered after a month of abstinence.Further, acute THC administration has resulted in abnormal performance on behavioral measures of emotional processing , amygdala reactivity , and altered functional connectivity and signaling in PFC regions.However, additional research is needed to confirm the influence of repeated THC exposure on affective outcomes in adolescents and young adults.Due to the neuromodulatory role of the eCB system, examining brain functional connectivity is an important outcome to study in regular cannabis users.These relationships can be examined during tasks and also at rest, when individuals are not actively engaging in any specific cognitive tasks, called resting state, or intrinsic functional connectivity.Connectivity patterns in frontolimbic regions continue to develop into late adolescence and emerging adulthood; prefrontal maturation purports enhanced emotion regulation and behavior inhibition capabilities, giving rise to a functional coupling between frontal and limbic regions.Collectively, the developmental changes in frontolimbic connectivity are thought to enhance socioemotional regulation, specifically via functioning within the amygdala, medial PFC, vmPFC, ACC, insula, and inferior frontal gyrus.A particular region within the PFC, the ACC, also undergoes significant age-related changes in intrinsic functional connectivity, particularly in rostral ACC subregions involved in social cognition and emotion regulation.Therefore, this system may be particularly vulnerable to repeated THC exposure during development.Thus far, studies have found slower response times in users when identifying emotional faces and more liberal criterion for selecting sadness , poorer facial recognition and emotion matching , and emotion identification and discrimination impairments compared to non-users; though accuracy in emotion identification may not display a dosedependent relationship.fMRI studies have found aberrant amygdala and ACC activity in young cannabis users during affective processing tasks, including blunted ACC and amygdala activation during sub-conscious facial viewing , blunted amygdala response among youth with comorbid cannabis dependence and depression , and greater amygdala reactivity to angry faces in young adolescents.