While research on the use of alternative containers for greenhouse production is growing, most studies have focused on a limited number of types of alternative containers and primarily on short-term greenhouse crops. With the recent release of several new bioplastic alternatives, comparisons to established alternative containers and production of longer rotation ornamental crops should be investigated. Our work, therefore, investigates the performance of ten commercially available alternative containers and their effects on both a short-term ‘Sunpatiens Compacta’ impatiens (Impatiens ×hybrida) and a long-term greenhouse crop ‘Elegans Ice’ lavender (Lavendula angustifolia) at four different locations. Results indicated that plant growth in terms of dry weight differed by container at most locations. Combined analysis of all locations showed that only straw and a bioplastic sleeve outperformed plastic pots in terms of shoot dry weight and then only after 12 weeks of production. Leachate pH, but not electrical conductivity (EC), varied by container in both the short- and long-term crop with alternative containers made from composted cow manure and peat showing consistently higher and lower pH readings, respectively. Postharvest container strength varied significantly by container, with the plastic control maintaining the highest puncture resistance after both 6 and 12 weeks, in some instances matched by the puncture strength of coconut fiber pots. Some alternative containers, in particular, wood, manure, and peat showed algal growth after 6 and 12 weeks of greenhouse production. We conclude that while some alternative containers were linked to increased growth, most showed growth equal to the plastic control, and could therefore make appropriate alternatives to plastic pots. However, changes in pH, low puncture strengths after production, higher denesting times, and algal growth on manure, wood, and peat may make these pots less desirable alternatives than other pots under investigation. However, other factors not studied here, such as compostability, biodegradability in the landscape, water use, consumer preference, aesthetics, compatibility with mechanized operations, and cost may also need to be taken into account when deciding on an appropriate container for greenhouse production.
Renee Conneway, Sven Verlinden, Andrew K. Koeser, Michael Evans, Rebecca Schnelle, Victoria Anderson and J. Ryan Stewart
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.