[Cavan Allen]

My experience has always been that it will grow the largest and widest thalli under strong light.

Make every reasonable effort to keep it contained. It's a nice plant, but it can be a problem if you let it become one. Please see my signature.

 

[Cavan Allen]

Well, as I mentioned in chat, plants that grow out in the open get rather large while the shaded stuff stays smaller. If it piles up really deep, the stuff below has that antler look and gets pretty scrawny.