Nancy, the reason fiddle leaf ficus do better when outside (in the right conditions, of course) is because they are trees, and trees are generally going to grow best outside. My fiddle leafs are all outside, and we will have lows down into the mid-40's. My plants do fine with those low temperatures. They are all under large oak trees though. I would prefer the night/morning temperatures to be at or above 55 F though. These are tropical plants and do best with more moderate lows. You don't want your tree to get any direct sunlight between 11 AM and 3 PM. The leaves will sunburn.
