Peat moss is anti-microbial. Microbes don’t grow well in it. That’s just the opposite of what we want.  Peat moss is good for storing bulbs or shipping food or other live material.   Potting soil should NOT BE  STERILE as some recommend, but alive and dynamic. It should be light, well aerated, full of microorganisms and have the ability to stimulate quick and sustained growth.

Pine bark is not good for plant growth. As it breaks down it forms some natural chemicals such as phenols and turpines that inhibit plant growth. It has been established in university tests that it does not support many of the beneficial microbes that prevent disease.