What Is Parafilm & How Do You Use It In Mushroom Growing? 

Hi and thanks for the instructions. I just bought 5 meters of parafilm and so far HAVE NOT figured out how to get the paper off the film. Aparently my fingernails are too coarse. Even tried my pocket knife without success. I wish you had shown THAT in this video. Much thanks though. I'm a newby to mushroom cultivation.

Thanks!

hello i didnt stretch the parafilm tape, does it affect the gaseous exchange into the petri dish?