Brown Mold in Saucer/Tray

[knauer91]

My ficus bonsai tree is potted with a saucer at the bottom for any water that drains down. I've been giving my plants extra attention and I've wondered what this mold is and the best way to tackle it. The plant is otherwise fine (to my knowledge) but I worry what this brown gunk may indicate. Google wasn't helpful so here I am!

 

[cpp gardener]

I don't think it's anything to worry about. It looks most like a Calcium/organic tannin deposit from your water and potting soil. If it's mushy, that may be a problem, but it really doesn't look problematic.