New Study Suggests Recycled Glass Could Boost Plant Growth.
Glass waste often ends up in landfills, but a recent study suggests that may not always be necessary. Researchers have found that ground glass particles can be combined with soil to create a plant growth medium that performs better than soil alone.
While large glass items are commonly recycled into new glass, small, mixed-color glass fragments are challenging to sort efficiently. Consequently, these tiny glass pieces are frequently discarded. To address this, scientists at The University of Texas Rio Grande Valley explored the potential of using ground glass as a substitute for sand in plant growth media. This approach could reduce landfill waste and lessen the demand for sand, which is becoming increasingly scarce.
Under the leadership of professors Julie Vanegas and Teresa Patricia Feria Arroyo, the team sourced glass particles from a company that crushes and smooths bottles destined for landfills. They mixed these glass particles, in various sizes, with commercial potting soil in different ratios, from 100% glass to 100% soil.
The researchers then grew cilantro, bell pepper, and jalapeño plants in these different media under controlled greenhouse conditions. They discovered that when the glass particles were about the size of coarse sand grains, they allowed optimal oxygen flow to the plant roots and maintained proper moisture levels. The rounded edges of the glass particles also prevented root damage.
However, the study noted that potting soil mixtures had higher nutrient levels, including essential elements like nitrogen, phosphorus, and potassium. Despite this, plants grown in media with more than 50% glass particles grew faster and retained more water than those in 100% potting soil. All media had similar pH levels.
The accelerated growth in glass-containing media was attributed to the absence of a fungus known to inhibit plant growth, which was present in pots with 100% soil. The researchers are investigating why the fungus did not affect plants in the glass-amended media.
The findings suggest that using recycled glass in agricultural soil could potentially reduce the need for fertilizers, pesticides, and fungicides. “Minimizing the use of harmful chemicals is crucial for public health,” says chemistry graduate student Andrea Quezada, who will present these results at the American Chemical Society’s fall meeting. “By reducing chemical use and promoting recycling, we can improve community well-being.”
The impact of glass particles on plant yield and taste will be assessed once the plants are harvested.