Worm castings or vermicompost and mushroom growing

Hi Kyle,
Using 100% worm cast/VC is never advisable. It will repel water, sometimes going very hard.
Using 10%-25% is usually what is recommended.

I’m not familiar with the growing medium makeup of a good mushroom compost – but there will be a formula somewhere that sets out ingredients to make a good medium, that has suitable air porosity and water absorption rates – just add your VC by % after making or buying the main growing media.

Remember, the good thing about VC is not it’s fertiliser value, which is low. It is great for all the things it adds to the soil mix.

If you want to read up on the advantages of VC here’s some info on my site:
thewormman.com.au/benefits/

Thanks for asking your question !

regards
Brian