In recent years, biocontainers have been marketed as sustainable alternatives to petroleum-based containers in the green industry. However, biocontainers constructed with plant materials that are highly porous in nature (e.g., peat, wood fiber, straw) tend to require more frequent irrigation than conventional plastic products. As irrigation water sources become less abundant and more expensive, growers must consider water consumption in any assessment of their economic and environmental viability. This project evaluated plant growth and total water consumption for nine different biocontainers (seven organic alternatives, and two recently developed bioplastic alternatives) and a plastic control used to produce a short-term greenhouse crop, ‘Yellow Madness’ petunia (Petunia ×hybrida). Dry shoot weight and total water consumption differed by container type, with some of the more porous containers (wood fiber, manure, and straw) requiring more water and producing smaller plants by the end of the trial period. Intuitively, the more impervious plastic, bioplastic, and solid rice hull containers required the least irrigation to maintain soil moisture levels, though shoot dry weights varied among this group. Shoot dry weight was highest with the bioplastic sleeve and slotted rice hull containers. However, the latter of these two containers required a greater volume of water to stay above the drying threshold. Findings from this research suggest the new bioplastic sleeve may be a promising alternative to conventional plastic containers given the current production process.
Andrew Koeser, Sarah T. Lovell, Michael Evans and J. Ryan Stewart
Andrew K. Koeser, Sarah T. Lovell, Aaron C. Petri, Robin G. Brumfield and J. Ryan Stewart
This study assessed the material and energy inputs required to produce a Petunia ×hybrida plant from initial propagation to delivery at a regional distribution center. Impacts were expressed in terms of their contribution to the carbon footprint or global warming potential (GWP) of a single finished plant in a ≈10-cm diameter container. Beyond this baseline assessment, the study investigated the secondary impacts (e.g., irrigation demand) associated with container type used. Life cycle assessment data were sourced from interviews, published literature, propriety data sources, direct metering at the greenhouse facility, and original findings from a series of university greenhouse experiments. Results show that a traditional plastic container accounts for ≈16% of overall CO2e emissions (0.544 kg) during petunia production. Although the container was a significant contributor to GWP, electrical consumption for supplemental lighting and irrigation during plug production proved to be the leading source of CO2e emissions (over 47%) in our model system. Differences in GWP when considering secondary impacts associated with the various biocontainers were minor, especially when compared with the other elements of production. Our results demonstrate that biocontainers could potentially be as or more sustainable than plastic pots once pot manufacturing and end-of-life data are considered. However, use of more efficient supplemental lighting sources may ultimately have the greatest impact on overall GWP for the production system assessed.
Youping Sun, Genhua Niu, Andrew K. Koeser, Guihong Bi, Victoria Anderson, Krista Jacobsen, Renee Conneway, Sven Verlinden, Ryan Stewart and Sarah T. Lovell
As the green industry is moving toward sustainability to meet the demands of society, the use of biocontainers as alternatives to petroleum-based plastic containers has drawn significant attention. Field trials of seven plantable biocontainers (coir, manure, peat, rice hull, soil wrap, straw, and wood fiber) were conducted in 2011 and 2012 at five locations in the United States to assess the influence of direct-plant biocontainers on plant growth and establishment and the rate of container decomposition in landscape. In 2011, container type did not affect the growth of any of the three species used in this study with an exception in one location. The three species were ‘Sunpatiens Compact Magenta’ new guinea impatiens (Impatiens ×hybrida), ‘Luscious Citrus’ lantana (Lantana camara), and ‘Senorita Rosalita’ cleome (Cleome ×hybrida). In 2012, the effect of container type on plant growth varied with location and species. Cleome, new guinea impatiens, and lantana plants grown in coir and straw containers were in general smaller than those in peat, plastic, rice hull, and wood fiber containers. After 3 to 4 months in the field, manure containers had on average the highest rate of decomposition at 88% for all five locations and two growing seasons. The levels of decomposition of other containers, straw, wood fiber, soil wrap, peat, coir, and rice hull were 47%, 46%, 42%, 38%, 25%, and 18%, respectively, in descending order. Plantable containers did not hinder plant establishment and posttransplant plant growth. The impact of container type on plant growth was smaller compared with that of location (climate). Similarly, the impact of plant species on pot decomposition was smaller compared with that of pot material.
Robin G. Brumfield, Laura B. Kenny, Alyssa J. DeVincentis, Andrew K. Koeser, Sven Verlinden, A.J. Both, Guihong Bi, Sarah T. Lovell and J. Ryan Stewart
Greenhouse growers find themselves under increasing pressure to respond to consumer preferences to use environmentally sustainable practices and materials while maintaining profitable operations. These consumer preferences reflect a mounting awareness of the environmental issues, such as climate change and their associated social costs. Ideally, sustainable horticultural production accounts for both traditional economic considerations and such social costs, some of which can be explained through the calculation of global warming potential (GWP). An obvious candidate for a sustainable intervention is the traditional plastic pot, which growers can replace with alternative biocontainers with varying degrees of GWP. This study calculates the variability of direct costs of production using alternative containers to offer a comparison of social and economic costs. We evaluated these direct costs of producing petunia (Petunia ×hybrida) grown in pots made of traditional plastic, bioplastic, coir, manure, peat, bioplastic sleeve, slotted rice hull, solid rice hull, straw, wood fiber, and recycled reground plastic containers used in a previous assessment of GWP. Our analysis of the costs when using a traditional plastic pot showed that the highest contributors to GWP were different from the highest contributors to direct costs, revealing that the price does not reflect the environmental impact of several inputs. Electricity, the plastic shuttle tray, and the plastic pot contributed most to GWP, whereas labor, the plastic container, and paclobutrozol growth regulator contributed most to direct cost of production (COP). At 64% of total cost, labor was the most expensive input. Watering by hand added another $0.37–$0.54 per plant in labor. When we analyzed input costs of each alternative container separately, container type had the largest impact on total direct costs. Before adding container costs, the direct COP ranged from $0.56 to $0.61 per plant. After adding containers, costs ranged from $0.61 to $0.97 per plant. Wood fiber pots were the most expensive and recycled reground plastic pots were the least expensive in this study. Based on our assessment and the observed small variation in GWP between alternative containers, growers would benefit from selecting a container based on price and consumer demand. Some social costs that we are not aware of yet may be associated with some or all biocontainers.