Reasons Why Vegetable Cultivation Increases or Does not Increase Vegetable Intake among Adult Vegetable Growers Living in a City in Gunma Prefecture, Japan: a Qualitative Study

We examined the reasons why vegetable cultivation increases or does not increase vegetable intake among adult Japanese vegetable growers. A qualitative cross-sectional study using a self-completed anonymous questionnaire was sent to participants (aged 20–74 years residing in three areas of a city in Gunma Prefecture, Japan) in September 2016. The questionnaire addressed perceptions of whether vegetable cultivation would increase vegetable intake, with four possible answers: strongly disagree, disagree, agree, and strongly agree. Respondents were then asked reasons for their view, with free-text responses. We also asked about participants’ characteristics and whether they found that growing vegetables had changed their vegetable intake and access to vegetables. We categorized the free-text answers by content. We analyzed 442 answers, and reasons for vegetable growing increasing vegetable intake were grouped into five categories: “availability,” “purpose of cultivation,” “quality,” “increased positive emotions toward vegetables,” and “unconsciousness”; for it not increasing intake were also grouped into five categories: “limited quantities,” “negative emotions toward vegetables,” “cultivation for a purpose other than eating vegetables,” “access to vegetables from other sources,” and “limits associated with self-cultivation.”

In the previous studies, the reasons why vegetable cultivation increases vegetable intake are discussed as follows: improvement of the accessibility of vegetables and fruits owing to the existence of the community garden (Barnidge et al., 2013), improvement of the availability of vegetables due to having a vegetable garden (Devine et al., 1999), and using vegetables naturally for daily meals due to the participation of community garden (Alaimo et al., 2008).However, empirical studies addressing the reasons why vegetable cultivation increases vegetable intake among adults remains scarce.In addition, there may be scenarios where vegetable intake is not increased by vegetable cultivation, e.g., in circumstances where only a few vegetables are grown, or if they are grown with the intention of being sold.By clarifying these, the understanding of the mechanism of the influence of vegetable growing on increased vegetable intake will be deepened.Thus, it may contribute to further effective practices that encourage increased vegetable intake by vegetable growing.It is therefore necessary to clarify the reasons for vegetable intake increasing (or not) as a result of vegetable cultivation.
This study aimed to examine the reasons why vegetable cultivation increases or does not increase vegetable intake among adult Japanese vegetable growers.This study addresses the question from a qualitative perspective.

Study Participants and Methods
We conducted a qualitative study using responses to an open-ended question in a self-administered questionnaire, drawing on data collected in a previous study (Machida & Yoshida, 2018c).Participants were residents aged 20-74 years from three areas of a city in Gunma Prefecture, Japan.We identified three geographic regions of the city: rural, suburban, and urban.Rural area B is located northwest of the city and vegetable cultivation flourishes there (607 households).Suburban area C is located in the middle of the city; vegetable cultivation flourished there once but now the amount of agriculture has reduced owing to land conversion for residential or commercial use (743 households).Urban area D, on the east side of the city, is the most urbanized region of the city (910 households).The questionnaire was sent to a total of 2,260 households, reaching about 3,000 residents aged 20-74 years, according to the most recent Japanese national census (E-stat, 2015).We collected survey data in September and October 2016 using a self-administered questionnaire.We mailed two sets of the questionnaire to all households in the three areas on September 12, using TOWNPLUS by Japan Post Co., Ltd.; this service helped us to send mail to all households in the selected areas, even without knowing the specific addresses.An explanatory letter and a stamped, self-addressed return envelope were enclosed with the questionnaire.We explained that (1) there was no need to reply if there were no residents aged 20-74 years in the household; (2) if there were three or more residents aged 20-74 years in the household, then two residents should reply; and (3) the survey was anonymous, and submitting a response would constitute consent to participate.In addition, we numbered each questionnaire so that we could identify from which of the three geographic areas each response came.

Survey Instruments
The questionnaire aimed to establish why vegetable cultivation increased or did not increase vegetable intake.First, participants were asked: "Do you think vegetable intake will be increased by growing vegetables?"A choice of four possible responses was given (strongly disagree, disagree, agree, and strongly agree).Participants were then asked to respond in their own words to the question: "Why do you think this?" Moroever, we asked participants' sex, age, cultivation style, and perceptions of changes in vegetable intake and the availability of vegetables as a result of vegetable cultivation.It is worthy to note that there were many farmers among the participants.However, a previous study has shown that 96% of farmers cultivate vegetables for home consumption (Machida & Yoshida, 2018b), so we deemed their inclusion appropriate.

Analysis
We divided participants into two groups according to their answer to the question: "Do you think vegetable intake will be increased by growing vegetables?" ("agree or strongly agree" vs. "disagree or strongly disagree").Responses to the above open-ended question were categorized using the grounded theory approach (Flick, 1995).We segmented the answers and identified reasons why respondents thought that vegetable intake would increase, or not, as a result of growing vegetables.We then coded the segmented answers and generated abstracted categories using these codes.These steps were repeated multiple times to ensure the validity of the results.We also calculated the perceptions of changes in vegetable intake and vegetable availability as a result of vegetable cultivation.Answers from those who said that there was no time when they had not grown vegetables were excluded.

Ethical Approval
This study was approved by the Gunma University Ethical Review Board for Medical Research Involving Human Subjects (Submission No.160074, approved on August 16, 2016).

Results
A total of 873 residents from 586 households responded (25.9% household response rate).Of these, 421 were excluded because they did not grow vegetables and 10 because they did not respond to the question: "Do you think vegetable intake will be increased by growing vegetables?"The study hence included responses from 442 people.
The distribution of respondents' characteristics is shown in Table 1.In total, 55 people (12%) thought that vegetable growing would not increase vegetable consumption (disagree), and 387 (88%) thought that it would (agree).By characteristics, those who responded "agree" in rural and suburban had high percentages, and those in urban were low (rural: 89%, suburban: 88%, urban 80%).The percentage of "agree" was higher among women compared with men (women: 89%, men: 85%).There was no difference in the percentage of "agree" by age (<60: 88, ≧ 60: 87).The percentage of those who answered "agree" by cultivation style was as follows: farmer = 88%, home gardener = 89%, community gardener = 33%, and others = 67%.0 0 10 100 * "Disagree" denotes those who responded "disagree" or "strongly disagree" and "agree" denotes those who responded "agree" or "strongly agree" to the question "Do you think vegetable intake will increase by growing vegetables?"The total number of responses included in the analysis was 442.
The subjective changes in vegetable intake and vegetable availability as a result of vegetable cultivation are shown in Table 2. Of the 442 participants who grew vegetables, 145 (33%) said that there had been no time when they did not grow vegetables, and were hence excluded.Of the remaining 297 participants, 172 (58%; in total of "increased" (77 [26%]) and "somewhat increased" (95 [32%]) said that their vegetable intake had increased since they began growing vegetables.There were 105 (35%) participants who answered no change, and few respondents answered "decreased" (2 [1%]) and "somewhat decreased" (13 [4%]).The participants of 217 (73%) said that the availability of vegetables had increased (in total of "agree" (118 [40%]) and "strongly agree" (99 [33%]).The participants of "Disagree" and "strongly disagree" were 63 (21%) and 10 (3%), respectively.The reasons for respondents thinking that vegetable cultivated increased vegetable intake (or not) are shown in Table 3. Reasons for this increase were placed into five categories, across 18 codes: "availability," of cultivation," "quality," "increased positive emotions toward vegetables," and "unconsciousness."Similarly, the reasons why vegetable cultivation did not increase vegetable intake were placed into five categories, across 13 codes: "limited quantities," "negative emotions toward vegetables," "cultivation for a purpose other than eating vegetables," "access to vegetables from other sources," and "limits associated with self-cultivation."

Discussion
This study attempted to clarify the reasons why vegetable cultivation did or did not increase vegetable intake among adults.The topic has not been widely studied; nevertheless, it is an important issue for public health.
Results will help to identify more effective intervention strategies to increase vegetable intake through vegetable cultivation.Of those who had not grown vegetables over a period of time, 58% answered that their vegetable intake had increased since they began to grow vegetables, and 73% observed that the availability of vegetables had increased.This suggests that vegetable growing improves both vegetable intake and the availability of vegetables.Perhaps, as discussed in previous studies, increased availability increases vegetable intake (Barnidge et al., 2013;Devine et al., 1999).
As to why vegetable cultivation increases vegetable intake, "availability" may be one of the key reasons."purpose of cultivation" may be a factor linked to availability.In other words, growing vegetables with the aim of eating them increases their availability and vegetable intake therefore also increases.The category "quality" may be related to safety, whether actual or perceived.Soil contamination can be a problem in community gardens (Alaimo, Beavers, Crawford, Snyder & Litt, 2016).However, participants seemed to feel "safe" and "worry-free" when managing the growing space themselves.The code "tasty" may be biased because of both the fact that participants equated taste with freshness and cognitive dissonance (Festinger, 1962).The code "increased positive emotions toward vegetables" suggests that participants may have developed greater attachment toward vegetables as a result of exposure (Zajonc, 1968).As a result, they may seek to avoid waste.Knowledge about vegetables develops through cultivation.Participants may thus become more interested in vegetables and find growing them fun as their knowledge increases, which in turn may encourage them to eat more vegetables.The code "unconsciousness" suggests that vegetable cultivation may steer participants toward increasing their vegetable intake at an unconscious level (Alaimo et al., 2008;Thaler & Sunstein, 2008).
Growing vegetables may therefore increased vegetable intake without the requirement for a conscious choice on the part of the grower.
Regarding the reasons why vegetable cultivation does not increase vegetable intake, the category "limited quantities" was used to refer to the amount that people can physically eat.For example, older people may eat less because they find it harder to chew and swallow.Some may be unable to eat, even if the supply of food is unlimited.Different approaches would be required to encourage these people to increase their vegetable intake.The category "negative emotions toward vegetables" was divided into reasons related to preference and those related to an absent sense of waste.People who do not like vegetables are unlikely to increase their intake because they have grown their own produce.Encouraged or forced to do so, they would likely waste considerable amounts.However, encouraging vegetable cultivation may help those who like vegetables or who are indifferent to increases in their vegetable intake.A number of respondents felt that "cultivation for a purpose other than eating vegetables" may not result in an increased vegetable intake.However, as previously noted, greater exposure to vegetables may have a subconscious effect on intake (Alaimo et al., 2006;Thaler & Sunstein, 2008).It is therefore possible that those growing vegetables for other purposes may also increase their intake, possibly without being aware of it.It is hence unclear whether this category is a genuine reason for vegetable intake not increasing or simply an unfounded perception held by some of the respondents.Vegetable cultivation may have no effect among those who are already getting enough vegetables from other sources, hence the category "access to vegetables from other sources."For example, a previous study in a rural area of Japan reported an interactive effect on vegetable intake between vegetable cultivation and participants being given vegetables (Machida & Yoshida, 2018a).In an area where vegetable cultivation flourished, many people grew their own vegetables; moreover, they were also given vegetables or able to purchase them from farmers' markets (Machida & Yoshida, 2018c).This area therefore had large numbers of people with high vegetable intakes (Machida & Yoshida, 2018c).Interventions to encourage vegetable cultivation may therefore be more effective in areas with little vegetable growing and where access to other sources or vegetables (e.g., supermarkets) is relatively poor.Some respondents commented on the "limits associated with self-cultivation."It may therefore be helpful to provide guidance to improve the effectiveness of interventions encouraging people to grow vegetables.This may require cooperation with professional growers and experts.
This study had some limitations.First, the methodology was only qualitative.Quantitative studies are therefore also needed to explore the findings over a larger sample.It also cannot be said that the data was theoretically saturated, as we did not use gradual theoretical sampling.However, a strength of the study was that we were able to incorporate data from a range of people, including those with different cultivation styles and living in three types of geographic area.

Conclusion
We clarified the reasons for vegetable intake increasing (or not) due to vegetable growing.As a result, there were five main reasons why vegetable growing both may and may not increase vegetable intake.In the future, quantitative studies are needed to explore the findings.

Table 1 .
Distribution of characteristics

Table 2 .
Subjective changes in vegetable intake and vegetable availability as a result of growing vegetables

Table 3 .
Reasons why vegetable growing increases or does not increase vegetable intake