Environmentally conscious consumers are generally willing to pay higher prices for sustainably produced goods and demonstrate loyalty to the retailers supplying them (Dennis et al., 2010; Krug et al., 2008; Yue et al., 2011). However, not all efforts to reduce the environmental impacts associated with commercial horticulture production have resulted in positive perceptions by the plant-buying public. For example, a recent study demonstrated that the adoption of organic fertilizers offered no significant marketing advantage for floriculture crops (Yue et al., 2011). In this same study, plants labeled as “organic” were actually viewed unfavorably by trial participants, although no explanation was given for this finding.
In contrast to organic labeling, the adoption of biocontainers (plant material-based, biodegradable pots) as an alternative to the use of conventional plastic containers can be a significant driver of consumer interest. Yue et al. (2011) found that biodegradable, compostable, and recycled pots had the greatest impact on consumer preference, outranking other sustainable production practices not seen directly at the garden retail center (e.g., efficient use of wholesale production space). Similar conclusions were drawn by Hall et al. (2010), who found container type contributed most to consumers' interest in sustainably produced plants, outranking other highly influential considerations such as price and carbon footprint.
Despite their perceived environmental benefits and appeal as alternatives to petroleum-based plastic pots, biocontainers have not been assessed to determine their overall impact on commercial greenhouse sustainability. In this regard, biocontainers have one obvious advantage over conventional plastic pots; they are not discarded and transported to a landfill after use. Rather, most biocontainers are designed to be planted directly into the landscape or composted in a home compost bin. Some bioplastics, however, may require commercial composting conditions to fully break down (David Evans, personal communication).
Although recycling plastic pots is an option for some consumers with access to collection facilities, containers used for greenhouse and nursery production are less likely to be reclaimed given the potential for chemical contamination and photodegradation (Garthe and Kowal, 1994). In the United States, overall, plastic recycling rates are estimated to be only 8% [U.S. Environmental Protection Agency (EPA), 2011]. Within this aggregation, not all plastics and plastic products are recycled equally. More ubiquitous and desirable products such as bottles and jars have recycling rates ranging from 21% to 28% (US EPA, 2011). Lesser-valued agricultural plastics are generally buried or burned and are likely reclaimed at rates much lower than the overall average (Garthe and Kowal, 1994).
Beyond end-of-life considerations, container selection can have a number of impacts on the overall sustainability of greenhouse production. Biocontainers vary in their material and overall strength (Evans et al., 2010; Evans and Karcher, 2004), and they can be less resilient to the rigors of mechanization and transport (Koeser et al., 2013a). As such, overall production efficiency may decline as a result of losses linked to unacceptable container damage. For potted plants that successfully navigate through mechanized transplanting and handling processes, plant growth rate and water use in greenhouse-growing spaces can vary given differences in container design and porosity (Koeser et al., 2013b). Moving beyond issues associated with production, purchased plants introduced into the landscape may have different establishment and growth rates depending on the combination of species and plantable pot used (Kuehny et al., 2011).
This study offers a first look at the overall sustainability of biocontainers as part of a greenhouse production system. Hall et al. (2009) noted in their survey work that greenhouse growers believed sustainability in their operations was important. Additionally, the researchers found that decisions regarding sustainable practices were largely based on this belief and not an expectation of economic reward from environmentally conscious consumers. As such, our work adopts a grower's perspective and focuses on the environmental impacts of container use during the plant production phase (cradle-to-gate).
One of the main difficulties in any life cycle assessment (LCA) is the collection of quality data from manufacturers and contractors (Boustead, 1996). Although this is true even for in-house assessments, the transparency and potential scrutiny that come with publishing results in a peer-reviewed journal can be an added barrier to full cooperation. In this assessment, only the secondary impacts occurring during the greenhouse production of plants (e.g., differences in irrigation demand, peat use, etc.) associated with each container are compared. These secondary impacts were directly measured through a series of applied research trials and represent differences in inputs growers would note in their operations. The results of this work can be used to guide future research by identifying promising containers for future assessment (i.e., determining the carbon footprints for their manufacturing). Furthermore, providing container manufacturers with preliminary results from a relevant example of the LCA process may reduce their apprehension and encourage future participation.
Biocontainers as a whole are marketed as a means of making the horticultural industry more sustainable. This article aims to provide one piece of the puzzle in evaluating these claims by identifying the extent to which each container impacts the carbon footprint of petunia production. The results of this work will help commercial growers identify secondary environmental impacts associated with their decision to adopt green packaging in their production systems.
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