Ok I am going to try micro clover if I can get my hands on it, if not white clover. Mirco Clover is just a selected white clover from what I have read, they select for less flowers and smaller plant. I think one of the benefits that I haven't see mentioned is that a cover crop will reduce the temperature of your medium through respiration, as well as covering and keeping your top layer moist. Not to mention the N fixing. I really don't know why this isn't a major thing yet. Guess I will find out soon enough