Q: What is the deal with PLA “plastics” made from cornstarch? A lot of the products I see say you have to compost them commercially. Wouldn’t they eventually breakdown anyways in a household compost pile?
A: Yes. The PLA plastics do break down eventually in back yard compost piles. The problem is that backyard composters may not reach the consistently high temperatures and conditions to break them down with any reasonable speed. Those PLA cups might live in your backyard bin for years. So they are not ideal.
Because we have much bigger piles than the usual backyard composter, we can handle the PLA plastic. Beware- there is a lot of green washing around these materials. Biodegradable does not equal compostable. Neither does “made from plants”, “eco friendly”, or “natural”.
The PLA products must meet “BPI certification” for us to take them. There are bunch of vendors out there that make compostable wares, but we like Ecoproducts and Greenware best.