Gabe15

They need a lot of inputs to compensate for the lack of root space, and they will still likely be smaller than in the ground. I would try using a potting mix that is very well draining and containing roughly 1/3 high quality compost, 1/3 soilless potting media and 1/3 perlite or something similar. You will need to water a lot, 1-2 times a day if it is warm. Removing /destroying suckers when they first show will limit growth to the main shoot and prevent the container from hopefully breaking from the force of the suckers.

But I doubt you can ever get a full size large plant in a container that small unless you really have some efficient hyrdoponic-type system going on, and even then who knows if it would work. Those large bananas are simply very large plants and they need a lot of space.

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Growing bananas in Colorado, Washington, Hawaii since 2004. Commercial banana farmer, 200+ varieties.