read the back of the label man .. seriously
fem seeds are bunk, because they are not guaranteed to do anything. Tampering with nature in that fashion is never good, sure you may get a few good females, but at the cost of turning hermi, which every fem has a good chance of doing, its better to buy normal seeds, and get the same amount of true females, with zero hermi traits.
Any stress whatsoever WILL turn fems into herms ..