I'm in zone 8 (Washington). I started growing them both in pots and in ground last year. In pots, I used just regular potting mix with cow manure. They are doing well, just put them in sunny spots and plenty of water. Mine are not big enough to produce so I don't know if my way of growing will be good enough. You can buy some fertilizers that are blended specially for bananas because they like potassium. Or you can add kelp meal. Stoke Tropicals sells humic acid that I think may help with flowering. By the way, don't leave them in ground over winter, it doesn't survive:-) I know but I had to try. Good luck.

yea zones are funny zone 8 in North Carolina where I am at is already at 90+ degrees in the day with 50% humidity and only dropping to around 79 in the evening. and will stay that way until around late Oct, early November.