Companion is Bracillus bacteria. It is a soil fungicide. Here is the spec sheet on the product.
http://www.growthproducts.com/docs/f...nion_2-3-2.pdf
OVE adds Bracillus to their worm feed and it is processed by the worms. It is interesting that adding the bracillus to the worm bins did not work.
So it is certainly safe to mix the two. I use companion as a method to increase the quantity of Bracillus in the solution. I have a cost factor in how much time I can devote to each plant so application is normally by sprayer. I mix worm tea, companion and the rooting hormones Essentials together and spray every two weeks.
The manufacture of Companion and Essentials says they can be mixed and since Bracillus is in worm tea already, I feel safe adding more.