I can't speak for banana seeds, but seeds in general need to have some sort of air circulation and not be kept in a confined ziplock bag. I tried this method with hot pepper seeds and needless to say, didn't have much luck. Try what you are doing now, but put the seeds in soil.

sounds like good advice. Don't scarify the seeds, the roots will develope out the hole thingy anyways.
GL

Hello Garden Guy
I am not sure why the method didn't work for your hot peppers. I start all of my peppers out this way. I do it for several reasons, the first is so that I don't waste my resources and second so I can get an idea of the viability of my seeds. I think the biggest thing is making sure that the towels arent too wet. I usually soak them then wring them out and this seems to work quite well for everything that I have tried to grow. I have read and heard that you should and that you should not scarify though. Maybe the two are not compatible?