I have been having this issue and so far it hasn't seemed to be a problem but I sure don't wan' to loos anything.
It is a green fungus/mold that is on top of the soil. I have been kinda rubbing it out till now but it may be growing. Any ideas as to what it might be or any ideas on what I can use to kill it. I have been putting Chamomile tea bags in with my water, last year I did that as well as cinnamon.