Originally Posted by pitangadiego
15-15-15 has worked well for me. Tried the 9-3-27 mixture that was supposedly optimum, but didn't see any difference, and it was considerably more expensive.
Professionally, 9-3-27 is a supplement used with Calcium Nitrate etc. to feed fruiting vegetables. I could see it being considered an "optimum" for bananas in conjunction with a base fertilizer in the few months leading up to bloom -- with the target being to provide net 1.5 lbs potash over the course of 9-12 months.
Certainly 15-15-15 with micronutrients will work -- but over time in the agricultural setting the phosphates will build up and the crop quality will be only moderate because of inadequate potash.