Bioplastics and biocomposites for sustainable horticultural containers: Performance and biodegradation in home compost

J.A. Schrader, K.G. McCabe, D. Grewell, W.R. Graves
The use of petroleum-based plastic containers for the culture of greenhouse crops has become standard practice worldwide. Although the effectiveness and versatility of plastic containers is unquestionable, the heavy utilization of non-degradable, single-use containers made of fossil materials is unsustainable and contributes heavily to the environmental impact of the greenhouse industry. Until recently, biorenewable alternatives to petroleum-plastic containers were limited to those made of bio-based fibers such as coir, paper, peat, or wood. Containers made of these materials are biodegradable, but they lack the functional advantages of plastic containers and have received little acceptance. Bioplastics and biocomposites show strong potential for use in containers that fulfill the advantages of plastic containers, but with much lower environmental impact. We created 18 novel biocontainers (16 injection-molded bioplastics and biocomposites, and two biopolymer-coated fiber containers), evaluated their effectiveness during crop production and their biodegradability in a home-compost system, and compared them with three commercially available biocontainers and a petroleum-plastic control. Of the 21 biocontainers evaluated, six of the injection-molded prototypes and one of the commercially available biocontainers degraded completely during the 12-week compost cycle. Two of the prototype containers and one of the commercially available containers biodegraded poorly in compost (‹12%), and paper-fiber containers, both coated and uncoated, degraded less than that of 13 of the bioplastic-based containers evaluated. In greenhouse trials, all but one of the eight highly compostable biocontainers were sufficiently durable for production of short- and medium-cycle greenhouse crops, and plants grown in these containers showed equal or greater health and dry weights to those grown in petroleum-plastic controls. Biodegradation in home compost can be a viable end-of-life option for many of these high-performing, biorenewable container formulations.
Schrader, J.A., McCabe, K.G., Grewell, D. and Graves, W.R. 2017. Bioplastics and biocomposites for sustainable horticultural containers: Performance and biodegradation in home compost. Acta Hort. (ISHS) 1170:1101-1108
sustainable practices, biorenewable, non-petroleum, biodegradable, waste reduction, biobased, green technology

Acta Horticulturae