Mold & pebble trays
I'm wondering if anyone can help me solve a mold issue that I'm having that I think is related to pebble trays.
I have three different plants on pebble trays (a goldfish plant, begonia, and prayer plant) that have started growing white, fuzzy mold on the outside of their terra cotta pots. It's definitely mold, opposed to a mineral buildup. The reason I think that this is related to the pebble trays is because all of my other plants are a)not on pebble trays, and b)not moldy.
So the question is: is the mold due to too much humidity, perhaps too much water actually touching the bottoms of the pots, or is it due to something that is being leached up from the actual pebbles (which I believe are granite chips, though not positive)? I tried placing the pots in saucers on top of the pebbles, which did not help.
I've never had a mold problem on the outside of a pot before, so any insight would be helpful.