That is why I don't use them. I even tried putting them in the oven.

thanks so maybe should not use them at all

I used them last year and had the same problem although it did not seem to do any damage to my plants as you can see from my photos the other problem that I had was keeping them from collapsing when they got wet the best way was to double them up so you have a much stable pot I am sure that the mould is something to do with the damp pots and warm greenhouse.I also took the plants out of the pots when they went into my garden.
Hope this helps

yes thank you

Hi HBS we would not use them but for a different reason - it takes thousands of years to make peat...