I've read online that you can compost perlite without a problem, and it actually has some benefits. I couldn't find information online that says that composting vermiculite is okay.

I know it is generally added to soil and has many benefits, but I want to know if composting is okay and if anything will happen to it during the decomposition time.

The reason I am asking is that I had a small mushroom growing on the bed of vermiculite. It has some mycelium in it, hence I wasn't sure if just putting it into the soil would be good. But also, I am just curious.

  • Careful adding the inoculated vermiculite to your compost as it could contaminate the entirety of it. Inherently, there is noting bad about adding vermiculite to compost; in fact, it is good for compost.
    – Rob
    Aug 6, 2018 at 17:48
  • @Rob, it contains an actual mycelium of an edible mushroom. No visible mold or anything else. Thanks for the comment! :)
    – Roman
    Aug 6, 2018 at 18:03

1 Answer 1


Vermiculite is exfoliated mica, a mineral. Therefore being non-vegetable in nature it cannot decompose into simpler compounds in a compost heap, but may shatter into smaller fragments due to abrasion. Its effect in compost would be like that in soilless mixes, promoting root growth by forming air channels and helping water retention. It occurs naturally in soils to varying degrees.

There appear to be some concerns regarding breathing shattered fragments of vermiculite since there is some association with asbestos for miners and end users (see asbestos contamination section in this article), but once mixed with moist soil airborne particles would be much minimized. Plain vermiculite does tend to cling to your fingers so adequate washing seems advisable.

  • Exactly, I just want to add though. There is defiantly a possibility that your inoculated vermiculite could eventually contaminate all of your compost.
    – Rob
    Aug 6, 2018 at 17:47

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