Originally Posted by Gabe15
I would avoid using pine bark or anything woody. As it breaks down, it will take away nitrogen which would otherwise go to the plant, so you will have to over fertilize to compensate. Since bananas are heavy feeders, it is tempting to feed a lot with sythetic fertilizers, but in a containerized situation they can easily accumulate and cause more problems than they are solving. For this reason, it is best to mix in most of the fertilizer ahead of time, and you can meet most of the nutrient requirements with a healthy portion of compost. You can also choose to mix in some slow release fertilizer too.
For long term growth in pots, I would use something like:
1/3 peat or coconut coir
I know what you mean, its better to use composted pine bark. However that nitrogen will become available again when it breaks down. I have not noticed any adverse effects using this mix on all my plants. I just compensate with fish emulsion fertilizer schedule and have been using kelp foliar sprays as well. Fruited bananas in containers with this mix, the mix works to counter the high PH water we have here in SoCal.