Mold – will not harm the worms. But if it is getting out of hand it likely means you are over-feeding (normally worms keep it in check). From a health perspective, if anyone in your house has a mold allergy, you might be best to keep the system outside – especially if you are fairly inexperienced. Lots of ways to keep fungal growth to a minimum (and certainly avoid having fruiting bodies that are releasing spores) but sometimes it is better to err on the safe side.

SHAUN – Any small system exposed to sub-freezing temperatures (without any sort of artificial heating) is a worm death-trap waiting to happen. It is amazingly easy to keep Red Worms alive in the cold (low-lying systems covered with lots of bedding materials) but smaller above-ground systems simply have no ability to ward off serious winter freezing. And even if the worms DO survive, the process itself slows to a stand still as temps drop. Sounds like you are talking about a somewhat bigger bin and you may be in a location where temps are more moderate than here in Canada, though, so you may do OK! When in doubt, try to keep a small insurance bin indoors as well.
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