technically in most places they will have to give you 24hrs notie before entering, but that doesnt mean that you landlord will. Also if there is any sort of emergency; fire, flooding, they will be in without notice. If you do decide to grow in a rental I would recommend you obviously be as stealth as possible, and try to stay as small as you can. I wouldn't use a whole bedroom, you may however have a decent storage space in the basement that may be utilized. Also try to find a place where you are payng for your own electricity if you are planning on doing any major lighting.