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I'm looking for a way to recycle biodegradable plastics myself and I was thinking about putting them in my wormery. Does anyone have experience with vermicomposting biodegradable plastics? Is it safe for the worms? Are there things to look out for?

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The general rule of thumb that I have heard is no. I can't seem to find a good resource at this time that breaks it out conclusively, but the logic that I have heard goes as follows.

Composting happens at different speeds and different heat levels. Your typical worm bin tends to operate at a low temperature (otherwise the worms would bake!). This would be slower normally, but the worms speed up the process.

As the overall heat increases (usually as a result of the proper mix of materials and frequent turning), the speed of the material breakdown increases. (For example a commercial system like this - http://www.hotrotsolutions.com/ - can yield compost in as little as 10-14 days according to their site.)

Generally, you need a hotter, more active system to really break down a lot of biodegradable plastics. Not that they won't eventually break down in your regular compost systems, but they likely won't break down as quickly as the other materials, leaving plastic pieces mixed in the compost.

The other consideration would be whether this adds any value to the worms. I have found vermicomposting to be like raising a pet, allows having to make sure that they have the right amount of food and water. Much of the material that you put in the system breaks down quickly because the worms are either eating it or using it as bedding. I guess that the plastic could be a form of bedding (this is pure speculation) but because I would assume that it would break down much slower than the newspaper that it more commonly used, it is likely to end up gumming up your system.

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    I think you are right. I just found this article which says that biodegradable just means it will degrade quicker than traditional plastic but may still contain toxic materials. Biodegradable doesn't mean it is compostable. – THelper Mar 11 '13 at 14:01
  • Also 'compostable' doesn't mean the plastic will turn into compost in your home compost pile or worm bin. For that the plastic should be 'home compostable' (more info here). – THelper Mar 7 '14 at 9:35
  • Wondering if there is any current scientific information on ability of worms to safely consume compostable bags? The bags I refer to are BPI Certified as Composable (not same thing as biodegradable) and have absolutely no petrochemical ingredients- 100% Non-GMO corn starch. I would assume that corn starch is safe for worms to eat, am I right? The bags can compost fairly quickly in my commercial compost facility, however they more often are windblown out of the windrow and become an eyesore and a chore. – Mary Apr 3 at 13:08
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It isn't a good idea to do so, the material from the plastic will build up in the worms bodies, and they will probably die. Also the compost could be toxic to the plants you are using it for.

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    could you add a source for the aggregation of plastic in the worms? – nairboon Apr 25 '13 at 20:44

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