just thinking, if i get a few spiders from the bathroom, and put them in my grow room would they beable to survive the heat and and kill them dam flys???

If you've got a bad problem with flys & insects why don't you try using a Fortefog mini fumer. They're very cheap and can be used anywhere in the home including the kitchen. I don't know whether it is advisable to use one if your ladies are in the last couple of weeks of flower, but i'm sure someone with more knowledge will let you know. They are very good to use to clean out a grow area before starting the grow. They use them in restaurants etc. Google it & read up about them, then you can decide.