Only ways to get seeds I know of is stress, which may mean feminized, or it was pollinated somehow. If you are outdoors and someone within roughly a two mile radius has a male and you are downwind just once, you'll have seeds. Only thing you can really do is finish her out and hope for minimal seeds. I grow outdoors and so far every year I've had at least a few seeds so I almost venture to call it normal, and a few seeds here and there aren't really going to destroy your crop. If you had a male in full bloom in your own garden then you would probably have the seediest weed of your life. I treasure a few good seeds that come out of a tasty bud, it means different genetics for me to grow and experience.