Mold growing on outside of clay pots

[josterha]

Hello All,

It's been a while since I posted, but I was hoping I could get some advice on this problem. I have six different pots sitting on pebbles in a humidity tray in my living room. I noticed the other day that there was a powder-ish substance on the outside of the pots. After I watered, it turned into a full-blown bluish mold. I think the same type of mold that you might find on old bread.

What should I do? I am allergic to mold, so I want to get rid of it ASAP. I am having allergy attacks. I read somewhere that many orchids use some fungi symbiotically in order to synthesize food (?). I have phals and oncidiums in the tray, and they all seem healthy. Most have been recently re-potted as well.

Should I add clean-out my humidity tray, possibly with bleach? Can I add anything to the water to kill the mold, but not harm the orchids?

I await your sage advice.

Thanks,
John