Development and evaluation of bioplastic containers for sustainable greenhouse and nursery production

Over 750,000 metric tons of petroleum-based plastics are consumed per year by the greenhouse and nursery industries in the United States for single-use plant containers. Approximately 98% of this non-renewable, non-biodegradable material is disposed of in the nation's landfills and represents an obstacle to long-term sustainability. Bioplastics show strong potential for use in plant containers that fulfill the functional advantages of plastic, yet are made of renewable, biodegradable materials that have a much lower environmental footprint. In 2012 and 2013, we created 46 novel biocontainers (35 injection-molded bioplastics or biocomposites and 11 biopolymer-coated fiber containers) and evaluated them in greenhouse, nursery, and landscape trials. Our greenhouse and nursery evaluations demonstrated that many of the injection-molded bioplastics function as well as, or better than, petroleum plastics for crop containers. Soy-based bioplastic containers released nitrogen, led to a fertilizer effect, and improved root morphology during crop production. Adding bio-based fibers to form injection-molded biocomposite containers reduced the cost and weight of containers and improved the processability, function, and biodegradation of the bioplastic materials. Coating fiber containers with bioplastics improved water-use efficiency during crop production and improved container durability and function to resemble those of petroleum-plastic containers. Results of landscape trials showed that many of the bioplastics and biocomposites degrade in soil under natural landscape conditions, suggesting that containers made of these materials could end their life cycle as degraded organic matter in soil, instead of entering the solid waste stream. Replacing petroleum-plastic containers with bioplastic containers could improve sustainability without sacrificing function.