Plant Nutritive Value of Composted Polylactic Acid (PLA) Plastic Ware.

Petroleum-based plastics are commonplace in the MSW stream of modern, throwaway societies. Once in landfills these plastics do not break down naturally in a convenient timeframe and take up large volumes of space. Compostable plastics, such as polylactic acid (PLA), offer a sustainable solution to problems with petroleum-based plastics. PLA is made from 100% annually renewable resources (corn in the U.S.) and is compostable at industrial composting conditions (high heat, high moisture). Once composted, the PLA is no longer visible; a new compost product is created—PLA-containing compost. However, research on PLA-containing compost nutritive value to plants is scarce. To test effects on plants from PLA-containing compost a greenhouse trial was conducted. Two PLA-containing composts (derived from peat moss, chicken feed and EcoProducts, LLC® PLA plastic ware; composted at 40°C and 50°C) were applied to the soil surface of young sweet corn plants grown in a temperate climate greenhouse setting. Evaluation of the two PLA-containing compost treatments was performed based on corn plant growth response and mineral nutrient status. Several controls were used for comparison, including a locally-obtained commercial compost brand and similar peat moss/chicken feed composts that did not contain PLA. Preliminary findings demonstrated that PLA-containing compost is not detrimental to plant health.