Abstract
In several regions of the United States, waste and “tag” wool are readily available, inexpensive, and considered low-quality because of weed seed contamination and stains from defecation. Because of an overabundance of waste and tag wool, some are landfilled. Previous research has indicated that wool or hair incorporated in potted plants can improve the water-holding capacity of the soil and act as a slow-release fertilizer. Furthermore, compost trials have demonstrated that wool produces a high-quality compost product. This study aimed to evaluate the market potential of wool-based compost to determine its commercial viability. To address this, we conducted in-depth interviews with lead user gardeners (n = 10) who used 1 yard of wool-based compost in their gardens over the course of 10 weeks and distributed a quantitative survey instrument to both lead users and general gardeners recruited from garden centers, nurseries, and horticulture classes (n = 256). Lead users responded positively to the wool-based compost and reported they would be willing to pay $6 to $7 per ft3. General gardeners who were less familiar with the product reported they were willing to pay at least a similar amount as that for typical market composts, but they suggested that they would pay more if characteristics such as “increases drought tolerance” were used in advertising. Our analysis indicated that the target audience for the wool-based compost is male gardeners older than 25 years who are concerned about the environment.
Records of composting date to the Akkadian Empire (2350–2150 BC), with clay tablets referencing the use of manure for agricultural purposes (Rodale 1960). Modern research has demonstrated that the benefits of using compost in crop production include improvements in soil fertility, porosity, and water-retention capacity, increased nutrient availability to plants, structural stability, and reduced erosion (Fitzpatrick et al. 2005; Pinamonti et al. 1997). Although composting is an ancient practice, there are limited compost feedstock ingredients, and compost is typically derived from sources such as livestock manure, bedding materials, crop residues, sawdust and shavings, and sewage sludge (Rynk et al. 1992).
Wool is not traditionally used in compost or as fertilizer, but it may be well-suited to amend several soil types, particularly alkaline soils in drought-prone areas. Wool acidifies soil, thus improving the pH for many garden and greenhouse crops, and it improves the water-holding capacity of soil in potted plants (Poston et al. 2005) because of its hygroscopicity (Zoccola et al. 2009). Wool also contains essential plant nutrients (Gershuny and Martin 2018), decomposes slowly, and acts as a slow-release sulfur, nitrogen, phosphorous, and potassium fertilizer under field or greenhouse conditions (Zheljazkov et al. 2005) and for potted plants (Poston et al. 2005).
It has been suggested that the addition of wool at 3.3 g⋅kg−1 of soil may support two to five harvests under greenhouse conditions and two to four seasons under field production conditions (Zheljazkov et al. 2005). However, raw wool contains impurities such as detergents and pesticides (Pearson et al. 2004) that could contaminate compost and soils (Fong et al. 1951).
Wool is nonperishable and can be easily stored until there is a positive market; however, in some regions and at certain times, wool is not commercially viable because of the lack of demand and/or excess storage from previous harvests. Excess wool and waste wool are currently landfilled or discarded, possibly creating environmental challenges (Zheljazkov et al. 2005). Therefore, an alternative market for wool needs to be identified.
The compost market in the United States is relatively large (Goldstein 2019; Sanders et al. 2011). On a national basis, the potential demand for compost is estimated to be an order of magnitude greater than the potential supply (Alexander et al. 2022). There is a significant body of research available on the benefits of sewage sludge, animal manures, and crop residues in compost, but there has been limited research of the use of other organic wastes, such as wool waste, as a soil amendment and nutrient source for crops (Zheljazkov et al. 2005). Disposal of keratin wastes, such as fiber byproducts from the wool textile industry and low-quality raw wools, represents a considerable environmental problem (Zoccola et al. 2009).
Because of the intermittent surplus of wool and/or existence of waste wool, it is possible to incorporate wool into compost, thereby diverting organic matter from landfills and creating a valuable soil amendment that brings economic value and environmental value to multiple industries. Although there is literature regarding the suitability of wool as a compost ingredient (Hustvedt et al. 2016), there have not yet been investigations of consumer acceptance of wool-based compost. This research is critical because retailers must address demands for horticultural products that combat drought and other stressors in gardens that may require the identification and marketing of novel products with which consumers are not familiar. Therefore, the purpose of this study was to evaluate the market potential of a novel horticultural product, wool-based compost, to determine its commercial viability.
Materials and methods
Wool-based compost
The compost evaluated for marketability in this study comprised a blend of wool considered “waste material” that was mixed with other organic typical materials commonly used in compost, including horse manure, woodchips, sawdust, dried grass clippings, food waste, and invasive aquatic plants (i.e., water hyacinth, Eichhornia crassipes). The resulting compost met quality standards of the industry for horticultural and agricultural applications (Hustvedt et al. 2016). Wool-based compost contained approximately 11% to 15% wool and had a carbon:nitrogen ratio of 13.80 to 14.10, depending on the sample and protocol (Hustvedt et al. 2016).
The Agricultural Analytical Services Laboratory’s U.S. Composting Council’s Seal of Testing Approval Program at Pennsylvania State University (University Park, PA, USA) evaluated the compost to determine the following characteristics: pH; soluble salt content or electrical conductivity; moisture content; organic matter content; total nitrogen; total carbon; carbon-to-nitrogen ratio; phosphorus; potassium; calcium; magnesium; particle size; arsenic; cadmium; copper; lead; mercury; molybdenum; nickel; selenium; and zinc. Respirometry and bioassay tests were also conducted to observe maturity and stability measurements of compost samples.
Sample
Protocols that involved human subjects were approved by the Texas State University Institutional Review Board (#3060), and written informed consent was provided before participation in the study. Participants were not financially compensated for their participation; however, they were provided incentives such as wool-based compost or packets of wildflower seeds.
Two convenience sample groups were selected for this experimental study: “lead users” and “general gardeners.” Lead users were gardeners who were interviewed in-depth after using the wool-based compost in their personal gardens. General gardeners were recruited from garden centers, nurseries, and horticulture classes and surveyed en masse. Lead users were recruited using posted advertisements on Craigslist™ (San Francisco, CA, USA) and NextDoor™ (San Francisco, CA, USA) that offered free compost to respondents who were self-described gardeners. The general gardeners were consumers recruited from garden centers, nurseries, botanical gardens, landscape trade shows, horticulture classes, and/or garden club meetings. These sample groups were chosen based on their willingness to participate and/or their experience with compost, gardening, or horticulture. Furthermore, targeting these two samples allowed for the inclusion of people who were predisposed to participating in niche markets associated with the product of interest, wool-based compost. This type of relationship marketing has been used to predict consumer behavior and potential markets (Etheredge et al. 2023a; Glover et al. 2014; Shani and Chalasani 1992).
Survey development
A quantitative questionnaire-based survey instrument was developed to identify the feelings of lead users and general gardeners regarding subjects related to environmentalism, local product use, behavior, and willingness to pay (WTP) for the wool-based compost. The instrument included the following six sections: Environmental Attitude, Environmental Behavior, Locality, Behavioral Intent, WTP, and Demographics.
The Environmental Attitude section included eight questions from instruments that were previously demonstrated to be reliable and valid (Cornelissen et al. 2008; Glover et al. 2014; Hustvedt and Dickson 2009). This section included questions such as the following: “I believe that I behave in an environmentally conscious way” and “When I buy a product, I take ecological considerations into account.” Responses were scored using a 5-point Likert scale, with 1 indicating “strongly disagree” and 5 indicating “strongly agree.” Nonresponses were uncoded. Scores for the questions in the Environmental Attitude section were summed, with a possible total score of 40 points. Individuals with scores ≤13 points had “poor environmental attitudes,” those with scores of 14 to 26 had “mediocre environmental attitudes,” and those with scores of 27 to 40 had “positive environmental attitudes.”
The Environmental Behavior section included eight questions adapted from previous instruments (Cornelissen et al. 2008; Glover et al. 2014), including “I believe that I behave in an environmentally conscious way” and “I consider myself a green gardener.” Similar to the Environmental Attitude section, responses were scored using a 5-point Likert scale and summed, with a possible total score 40 points. Individuals with scores ≤13 points had “poor environmental behaviors,” those with scores of 14 to 26 had “mediocre environmental behaviors,” and those with scores of 27 to 40 had “positive environmental behaviors.”
The Local Product Use section included six questions related to the respondents’ purchases of local products that were derived from previous research (Glover et al. 2014; Hustvedt and Dickson 2009). Examples of questions (scored using a 5-point Likert scale) were “I prefer to buy locally” and “I typically buy compost at a local garden center.” Respondents were also asked how often they bought various food products locally, and the responses were scored using a 5-point Likert scale, with 1 indicating “not at all,” 3 indicating “occasionally,” and 5 indicating “very often.” Scores of each item were summed, with a possible total score of 30 points; higher scores indicated greater interest in and use of local products. Individuals with scores ≤10 points had “low local product use,” those with scores of 11 to 20 had “medium local product use,” and those with scores of 21 to 30 had “high local product use.”
The Behavioral Intent section included six questions to determine the likelihood that the respondent would purchase the wool-based compost. Examples of questions include “I intend to use eco-friendly compost in my garden in the next year” and “I bought compost in the last year.” Score possibilities were “yes” (1 point) or “no/does not apply to me” (0 points). Scores for each item were summed, with a possible total score of 6 points; greater intent to purchase was associated with higher point values. Those with scores ≤2 points had “low behavioral intent/compost product use,” those with scores of 3 to 4 had “medium behavioral intent/compost product use,” and those scores of 5 to 6 had “high behavioral intent/compost product use.”
Questions in the WTP section were adapted from Batte et al. (2007). Participants were asked how much they would be willing to pay for a bag (1 ft3) of the wool-based compost while viewing the product. Options were $0, $1 to $3, $4, $5, $6, or ≥$7; this price range was based on the price for the same amount of compost at four commercial stores in the central Texas area. This section of the instrument also gauged respondent’s WTP based on the compost characteristics. Participants were asked questions such as the following: “Assuming bags of compost are priced at $3.00 per bag at your local nursery/garden center, how much more (if any) would you be willing to pay for each of the following characteristics?”. The possible characteristics were “diverting organic materials from landfills,” “locally produced,” and “helps better protect against drought stress.” Answers were scored using a 5-point Likert-type scale, with 0 indicating $0, 1 indicating $1, 2 indicating $2, 3 indicating $3, 4 indicating $4, and 5 indicating ≥$5 extra per bag (1 ft3).
Respondent demographics were gathered using questions adapted from previous instruments (Glover et al. 2014; Hustvedt and Dickson 2009) and included questions regarding age, education level, household income, ethnicity, and sex.
Before distribution, an expert panel of horticulture, agricultural business, marketing, and focus group researchers (n = 3) reviewed the survey instrument. Feedback was solicited during the review process, and the survey was revised until the expert panel approved the final version. The instrument was subsequently pilot-tested during a postsecondary horticulture course (n = 35) at a regional university in central Texas. Cronbach’s reliability test indicated α = 0.77, which is acceptable (Gall et al. 2007).
Lead user sample, quantitative survey, and interviews
Lead users are users whose present strong needs will become general in a marketplace in the future (von Hippel 1986). For this study, lead users were active gardeners from the greater regional area of Austin, Texas, USA. Lead users (n = 10) were recruited through an advertisement on Craigslist™ and NextDoor™ that offered free compost to respondents who were self-described gardeners. Because lead users were questioned in-depth, this component of the study was considered “phenomenological” and required a certain number of participants (n = 6–10) to produce usable data (Morse 2000).
Lead users were provided 0.5 yard3 to 1 yard3 of the wool-based compost and asked to use it during a 10-week gardening season. Before receiving the wool-based compost, lead users were briefed about the basics of the wool-based compost and asked to use it in place of, or adjacent to, the blend they typically used.
After the 10-week gardening season, lead users completed the quantitative survey-based instrument described and completed an interview. Interview questions were asked by a single researcher, and the lead user was allowed to respond freely. If clarification was needed, then the interviewer asked for more information or provided additional prompts. Interview questions included the lead users’ initial impressions of the wool-based compost, i.e., “When you used your compost for the first time, what was your impression of the odor/the texture?” and “As you applied your compost to your landscape/gardens, did you notice anything about it that stood apart from your typically-used compost?”. Furthermore, the interview gauged the relative importance of physical parameters of the compost (e.g., texture, porosity, structure, odor) to the lead user because these physical parameters are associated with quality soil amendments (Mahfooz et al. 2006).
General gardeners and quantitative survey
General gardeners (n = 256) recruited from garden centers, nurseries, and horticulture classes completed the quantitative survey instrument described while viewing a 2-gallon sample of wool-based compost.
Data analysis
Quantitative data from the survey instrument were analyzed for descriptive statistics and frequencies using statistical software (IBM SPSS Statistics version 22.0; IBM Corp., Armonk, NY, USA). Data were analyzed separately for general gardeners and lead users. For general gardeners, demographics were also analyzed to investigate whether there were different responses within or between groups using an analysis of variance. Pearson’s Product-Moment tests were used to analyze trends in behaviors and attitudes in relation to WTP to identify the target customer base for wool-based compost.
Qualitative interview data from lead users were analyzed inductively by two authors to determine themes. The two authors independently familiarized themselves with the data, searched for themes, merged redundant or similar themes to develop meaningful and comprehensive themes, and refined theme names. For questions that requested facts rather than attitudes, the responses were tabulated.
Results and discussion
The purpose of this study was to evaluate the market potential of wool-based compost to determine its commercial viability. To address this, we conducted in-depth interviews with lead user gardeners (n = 10) who used 1 yard of wool-based compost in their gardens over the course of 10 weeks, and we distributed a quantitative survey instrument to both lead users and general gardeners recruited from garden centers, nurseries, and horticulture classes (n = 256).
Lead user interviews
Of the lead users (n = 10), 20% were 25 to 44 years old, 50% were 45 to 59 years old, and 30% were 60 to 84 years old. Additionally, 80% were male and 20% were female. Household incomes varied, with 30% of lead users earning $35,000 to $74,999 annually, 10% earning $75,000 to $99,000 annually, 50% earning $100,000 to $149,000 annually, and 10% earning ≥$150,000 annually. Education levels also varied: 10% of lead users completed some high school but did not receive a diploma, 30% were high school graduates or equivalent, 20% earned an Associate’s degree, 20% earned a Bachelor’s degree, and 20% earned a Graduate or Professional degree. The demographics of our lead users were comparable for education and income levels but skewed slightly younger than those involved in a study that described 73% of national extension Master Gardeners as baby boomers (Dorn et al. 2018).
After using the wool-based compost in their personal gardens, lead users were interviewed and shared their reactions to the product. When asked how the compost was used in their gardens, lead users reported using the wool-based compost as follows: as a top dressing (50%) for vegetable beds, trees, or ornamental beds; mixed with soil to plant trees (30%); tilled into soil for vegetable beds (20%); or as mulch (10%). Eight (80%) of the lead users seemed to be willing to purchase the product if it became commercially available. One lead user (10%) indicated the need for more information about the safety of the wool-based compost and stated that the wool may be toxic. Another lead user (10%) was concerned about whether the animals yielding the wool had been ethically treated. The mention of animal ethics was interesting and would likely need to be addressed if wool-based compost were commercialized because the consumer concern for livestock welfare has increased in recent years (Alonso et al. 2020; Bozzo et al. 2019) and may influence purchasing decisions.
When asked for their impressions of the appearance of the wool-based compost, lead users were fairly neutral, with 60% describing the texture as chunky, 30% describing it as rich or thick, and 10% describing the presence of wool as “weird” and that it could potentially “gross some people out.” Lead users responded neutrally or positively about the odor of the wool-based compost; 80% were neutral and 20% liked the smell, which they described as “earthy.” When asked about the color of the wool-based compost, 50% of lead users characterized it as “good” or “fine,” 40% reported that is looked “dark and rich,” and 10% reported that the color appeared “like quality compost should.” Of the lead users, 60% could detect bits of wool that were characterized as “strange, but not uncomfortable,” and one of these respondents added that some people (but not that person) might not like the appearance of the wool and wondered if it could be shredded further to disguise its presence in the final product.
There has been little research about how the appearance of compost impacts consumers’ acceptance of the product or influences purchasing decisions. Roxburgh et al. (2020) demonstrated that the attributes of samples of composted, granulated fecal sludge (i.e., color, texture, odor) impacted Malawian farmers’ acceptance of the product. In the United States, high-quality compost is tested and meets standardized criteria (Ozores-Hampton 2017). Although there is not an established “optimal” range for particle size, 86% to 93% of the compost sample used in the current study had a particle size <9.5 mm (Hustvedt et al. 2016). This is less than that of another novel compost product (Jasso et al. 2023) and may indicate that composting did not degrade the wool to a particle size that consumers find acceptable. Waliczek et al. (2023) composted human hair and pet fur and described the presence of large swaths of hair in the finished product; although a high-quality compost was achieved, the researchers hypothesized there could be negative sensory reactions to the visible hair particles and recommended further research of consumer acceptance. Our findings confirmed their hypothesis and suggested that the presence of visible wool, hair, or fur particles in finished compost products may elicit negative reactions from certain consumers.
We prompted lead users by reminding them that their region (i.e., central Texas) has recently experienced severe droughts, and that “compost that holds water is presumed to be a good thing.” Then, we asked about their observations of the water holding capacity of the wool-based compost. Half of lead users (50%) thought the wool-based compost had superior water retention characteristics compared to previous composts they had used, 40% did not notice a difference or were unsure how well the wool-based compost retained water, and 10% opted out of the question. We also asked lead users to rate the quality of plants grown in the area in which the wool-based compost was used; 10% observed heightened plant quality after using the wool-based compost, 40% reported that the plant quality was equal or better to that during previous seasons, 20% observed plant quality that was the same as that with compost used during previous seasons, and 30% did not use the compost in an area where plants grew.
To explore characteristics of the wool-based compost that may entice lead users to purchase it, we asked the following: “If you knew this product kept organic matter out of the landfill, would it encourage or discourage you from buying it?”. A majority of lead users (80%) indicated this knowledge would encourage them to purchase the wool-based compost, and 20% indicated they would be encouraged to purchase the product if the price was the same as or less than that of an alternative compost.
All lead users (100%), when prompted for additional questions or comments, responded positively. Example statements were as follows: “Overall, this compost was as good as any I have tried. I like the idea it was using recycling to save landfill space. I would definitely buy it, if it were available” [sic]; “Your compost was a positive overall experience for me.”; “Seems like a good idea. If the fur could get broken down more, that would be good.”; “I think this is quality compost and a good idea!”; and “Seems like a good product to sell.” Lead users also emphasized the environment in the following feedback: “It could be marketed as an environmental choice bonus. I think it might need to be tested, but it seems like a great idea!”; “I collect leaves for the same reason.”; “I would be interested to find out more about this crazy, new concept!”; and “Yes, I will buy it and protect Mother Earth. I love the idea of a wooly compost or a dog hair or human hair… whatever!”. We also received the following feedback about the visual appearance of the wool: “Large-scale production might break down the wool completely. I think the wool might be a problem for some.”
Lead users and quantitative survey
All 10 lead users (100%) had scores in the “positive” category of the Environmental Attitude section, with a mean score of 37 (possible score of 40) points, indicating attitudes that strongly favored ecological and environmental considerations. Three lead users (30%) had a score of 40, which was the highest score possible. Furthermore, all of the lead users (100%) had scores in the “positive” category regarding Environmental Behaviors, with a mean score 34 (possible score of 40) points. Most of the lead users (90%) had scores in the “high” category and one (10%) had a score in the “low” category of the Local Product Use section, with a group mean score of 22 (possible score of 30) points. In the Behavioral Intent section, 50% of lead users had scores in the “high” category and 50% had scores in the “medium” category, with a group mean score of 4.3 (possible score of 6) points.
Regarding WTP, 40% of the lead users would be willing to pay $6 for a 1-ft3 bag of wool-based compost, whereas 60% would be willing to pay ≥$7 per bag. When considering potential value-added characteristics that could be used in advertisements (e.g., whether the material would protect against drought stress or was locally produced), lead users consistently reported they would pay more for the wool-based compost if the product had these characteristics (Table 1). Among all of the value-added characteristics, 50% of lead users reported they would pay $3 more per 1-ft3 bag if they knew the product would divert organic materials from landfills.
Lead users’ (n = 10) and general gardeners’ (n = 256) willingness to pay (WTP)i incrementally more than the base price for wool-based compost [1 ft3 (0.028 m3)] based on certain characteristics.
General gardeners and quantitative survey
General gardeners were recruited from garden centers, nurseries, and horticulture classes (n = 256). Of our sample, 66% were female and 34% were male. Most participants skewed younger, with 70% being younger than 25 years of age, 24% being 25 to 44 years of age, 4% being 45 to 59 years of age, and 2% being 60 to 84 years of age. Most general gardeners (61%) had completed some college but had not earned a degree, 17% had earned an Associate’s degree, 15% had earned a Bachelor’s degree, and 2% had earned a graduate or professional degree.
Although the sample of general gardeners was younger and less educated than the national population, it has been reported that people 18 to 34 years of age occupy 29% of all gardening households, and that 38% of this same age group planned to spend more time participating in lawn and garden activities in the following year (Baldwin 2018). Therefore, our sample population reflects a captive gardening audience rather than being nationally representative, which is appropriate for the scope of this research.
Few of the general gardens had scores in the “mediocre” category for Environmental Attitude (1.2%), and the majority (98.8%) had scores in the “positive” section (98.8%). The mean score for the Environmental Attitude section was 36 (possible of 40) points. For the Environmental Behavior section, 14% of general gardeners had scores in the “mediocre” category, with 86% having “positive” environmental behaviors, for an overall mean of 30 (possible score of 40) points. The Local Produce Use section was split across “low” (3% of sample), “medium” (47.5%), and “high” (49.5%) categories, with an overall mean score of 21 (possible of 30) points. The mean score in the Behavioral Intent section was 3.12 (possible of 6) points. A small percentage (7.5%) of general gardeners had a score of 0 points, indicating they responded negatively to all questions regarding compost purchases, with 26% categorized as having “low” behavioral intent, 44.2% categorized as having “medium” behavioral intent, and 22.3% categorized as having “high” behavioral intent.
Among general gardeners, 2% reported they would not be willing to pay for the wool-based compost, 19.9% reported they would pay ≤$3 or less per ft3, 31.7% reported they would pay $4 per ft3, 29.7% reported they would pay $5 per ft3, 10.2% reported they would pay $6 per ft3, and 6.5% reported they would pay ≥$7 per ft3. These findings indicate that the general gardeners we surveyed viewed the wool-based compost favorably because very few reported they would not be willing to purchase the product whatsoever. During similar research that evaluated consumers’ perceptions of a novel compost containing invasive seaweed, Waliczek et al. (2020) reported that although the majority of consumers did not have experience buying and using compost, they were supportive of the product. The inclusion of novel ingredients does not seem to negatively affect the consumers’ interest in compost.
Most general gardeners reported they would pay more than the base price ($3 per ft3) for the wool-based compost if phrases advertising the benefits to their garden or the overall environment were used (Table 1). More specifically, general gardeners would be willing to pay $1 more per bag if they knew the product protected against drought stress (28.8%), was locally produced or produced in Texas (35.5%), added slow-release nutrients/fertilizer to the soil (27.2%), or was naturally based (24.9%). Additionally, 20% of general gardeners reported they would pay $2 more per bag if the product was advertised as diverting organic materials from landfills.
These data are in agreement with those of previous research that was also conducted in the central Texas region and evaluated the influence of certain product characteristics on the marketability of seaweed-containing compost (Waliczek et al. 2020) and indicated if environmentalism is emphasized in advertisements for specialty composts, then consumers will be willing to pay more for the product. Interestingly, previous research indicated that a majority of consumers in the northeastern United States would not pay more for pro-environmental products, and that many would actually pay less, perhaps because of the psychological reactance theory (Barber et al. 2014). However, our sample population likely valued environmentalism to a greater extent and was more influenced by environmental marketing messages than the general population surveyed by Barber et al. (2014), as indicated by the mean scores for both lead users and general gardeners in the Environmental Attitude and Environmental Behavior categories.
There are clear differences in the base price and additional price increments that lead users and general gardeners reported being willing to pay for the wool-based compost if they knew certain characteristics about the product (Table 2). All of the lead users would pay ≥$6 per 1 ft3 of the wool-based compost, whereas only 16.7% of general gardeners would pay the same. The lead users in our study also seemed to be more motivated than the general gardeners to pay more than the base price for value-added characteristics. The only characteristic that any lead users reported they would not be willing to pay more for was “is a naturally based product” (10.0% of lead users), whereas 12.4% to 18.4% of general gardeners reported they would not pay more than the base price for any of the characteristics on the survey. This was expected because lead users are typically early adopters (Rogers 1995) who are at the forefront of a particular market or industry (Franke et al. 2006) and may be willing to pay a premium for innovations that address their specific challenges or provide added value. However, the ability to fairly compare the responses of lead users and general gardeners in our study may have been limited because lead users completed the quantitative survey after using the wool-based compost in their home gardens for a season, whereas general gardeners responded after a brief interaction with the product.
Correlation between general gardeners’ (n = 256) willingness to pay (WTP)i for wool-based compost [1 ft3 (0.028 m3)] and scores of various scales that may influence purchasing decisions.
Correlations between scores and WTP
For the general gardeners, Pearson product-moment correlations indicated a positive and significant relationship between Environmental Attitude scores (r = 0.13; P = 0.03) and WTP, Environmental Behavior scores and WTP (r = 0.14; P = 0.03), and Behavioral Intent and WTP (r = 0.20; P < 0.01). In each case, as the scores became more positive for the variable of interest, WTP also increased (Table 2). There were no significant correlations between Local Product Use scores and WTP.
Cumulatively, these data indicate that consumers who have intrinsic environmental motivations, display environmentally conscious behaviors, and are likely to purchase or use compost would be willing to pay more for a bag of wool-based compost (Table 3). Previous research has established a positive correlation between consumers’ level of environmental consciousness and WTP for an environmentally certified agriculture product (Vlosky et al. 1999). Furthermore, there is a positive relationship between the environmental affect and purchase intention (Grimmer and Woolley 2014). Therefore, it was not surprising that we also identified a positive relationship between Environmental Attitude, Environmental Behavior, and WTP for wool-based compost.
Messages derived from a data analysis and literature review to effectively market wool-based and other sustainable compostsi.
The lack of correlation between Local Product Use and WTP in the present study contrasted with previous findings of Waliczek et al. (2020), who reported a positive relationship between local product use and WTP for a specialty compost containing seaweed harvested from regional waterways. Perhaps the reasons underlying our findings were related to the population. Although the sample surveyed by Waliczek et al. (2020) also resided in central Texas, it included patrons of general farmers markets, churches, and community centers, whereas our sample was surveyed from garden centers, nurseries, and horticulture classes. The general public is willing to pay a premium for local products, whereas consumers who have experience with a particular product place a much smaller value on the local attribute (Adalja et al. 2015). Therefore, the locality of compost that contains novel ingredients may not influence the purchasing decisions of experienced gardeners, but it has the potential to appeal to first-time or early users.
Demographic comparisons of WTP among general gardeners
There were significant differences in WTP across many demographic comparisons (Table 4) for the general gardeners sample. Regarding sex comparisons, males were willing to pay significantly more for wool-based compost than females (P = 0.03). Approximately 30% of males were willing to pay ≥$6 per bag of wool-based compost compared with only 14% of females.
General gardeners’ (n = 256) analysis of variance (ANOVA) and frequency comparisons of willingness to pay (WTP) for wool-based composti.
The role of sex has been well-researched by WTP analyses and is often considered the strongest predictor of environmental behavior, followed by income, education, and age (Olli et al. 2001). Women and men have different interests and needs related to the environment (Asteria et al. 2014) that presumably can be extended to decisions about compost purchasing. However, previous studies that investigated the relationship between sex and environmental attitudes or behaviors are inconsistent (Etheredge et al. 2023b; Fransson and Garling 1999). Furthermore, there is no relationship between farmers’ sex and willingness to produce or use compost (Al-Madbouh et al. 2019; Majbar et al. 2021). Therefore, although our data suggest that men are more likely consumers of wool-based compost, this finding is likely nuanced and requires further exploration to determine if underlying subjective norms, moral norms, or perceived behavioral controls are more appropriate explanatory variables of WTP for wool-based compost (López-Mosquera 2016).
There was a trend for the level of education to impact WTP (P = 0.08), although the trend was indiscernible, as reported by previous research (Waliczek et al. 2020). Income significantly affected WTP (P = 0.02), with those in higher income categories reporting a higher WTP in general. These findings align with previous research that demonstrated an increasing WTP for environmental goods associated with higher incomes (Baumgartner et al. 2016). Age also significantly affected WTP (P = 0.03), with older respondents having higher WTP. However, this finding may be explained by a general positive association between age and income.
Conclusion
After using wool-based compost in their personal gardens, lead users indicated they would purchase the product at a premium. General gardeners were also supportive of the wool-based compost and reported they would pay more than the base price if they were aware of certain product attributes; however, the premiums they would pay were lower than those that lead users would pay. These data indicate that if wool-based compost were to be offered in garden centers and nurseries, then the product could potentially be presented as a high-value specialty compost that would be economically advantageous for retailers.
Our data indicated that the target audience for wool-based compost comprises consumers who have more positive environmental attitudes and behaviors and have bought or intend to buy compost. Demographic comparisons demonstrated that males, individuals older than 25 years old, and those in higher income brackets had greater WTP for the wool-based compost. These specific groups would be ideal to target using advertising, and pro-environmental messaging, especially regarding waste diversion from landfills, should be used.
Feedback from lead users mentioned a potential barrier to the general acceptance of wool-based compost (i.e., the visible particles of wool may cause disgust or negative reactions, especially in less experienced gardeners). As commercialization of wool-based compost is realized, upstream processors should be aware of the potential challenges associated with the presence of large particles of wool in the downstream product and should adjust composting protocols to ensure adequate degradation and particle size in the final project.
The study limitations included the use of a convenience sample regionally based in the southern United States that included a high percentage of younger gardeners. Therefore, extrapolation and generalization of these results to other populations should be performed with caution. Additionally, the results represent the stated preferences of lead users and general gardeners rather than the actual revealed preferences that would have been demonstrated through true purchases of compost and/or product investment. We recommend further research of the general attributes and marketing messages that influence consumers to purchase certain compost or related horticultural products. We also recommend studying preferred compost purchases and WTP through choice experiments. Additionally, it may be worthwhile to investigate other organic materials currently in the waste stream and ask respondents to rank the diverted compost materials that they would value most.
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