Most of my life I have been a tinkerer and once I played with idea of coffee grounds as a potting medium. I found the coarse grounds from a Walmart house brand was worth a second try but soon failed to be worth the effort. The grounds from Starbucks had a lot of espresso grounds in them and just formed an unmanageable ball. Final results; I think a fairly large amount of the cheap grounds 10-20% perhaps, could be mixed in with a potting soil.
