Got a green dilemma? Ask me! I'll be answering a new question each week.
Q: Is it better to use compostable dog-waste bags or re-use plastic bags?—Ron Andersen, Eugene, OR
A: I hate to be a spoiler, but “compostable” or “biodegradable” plastic bags, even those made of corn- or potato-derived bioplastic (PLA), will not decompose in less than a decade or so unless submitted to temperatures of at least 140 degrees in a municipal or industrial composter. (The Biodegradable Products Institute's “compostable” seal assumes that these conditions will be met.) Bioplastic bags will certainly not biodegrade in a landfill, which is where they go when you toss them in the trash, because they will be deprived of the oxygen and sunlight that enable anaerobic bacteria to do their digesting. Nor is it a good idea to put pet waste in your garden compost pile, because it can spread disease.
Reusing is always greener than buying new, so I’m all for using the conventional plastic bags you’ve got. After exhausting your supply, why not delve into your paper recycling bin and use biodegradable pages from old magazines and newspapers? You can bury the waste in a pit, away from vegetable gardens and streams, where it will return to the soil over the years.
But if you must buy plastic bags, then yes, buy bioplastics or recycled plastics rather than new petroleum-made plastic.
Mindy Pennybacker is Whole Living’s “Econundrums” columnist. See her answers to reader questions and ask your own here. She is also editor of GreenerPenny.com and author of Do One Green Thing: Saving the Earth Through Simple, Everyday Choices.