Banana Style pollen sacs but no seeds forming..

Ok I though some one thats been trying to hermi 4 plants. they tried everything light/cold air ect.. about 2 weeks ago or so banana style pollen sac started showing up just a few of them. But there is still no sign of seeds being formed it's now week 7 into flowering... any ideas on how to get these girls to produce seeds before there done. thanks