I have used a similar formulation of water soluble fertilizer on an Ensete M. I kept on my back deck last summer. I'm guessing a person could use the same for an inside plant, but I would think only in a 1/2 or even 1/4 strength. My concern would be buildup in the limited soil of even a large pot by the various salts used to make the fertilizer. Being outside, my plant got regular leaching out of the soil mix by rainfall and extra watering during warm periods. I would prefer to use something like sterilized earthworm castings instead, which would add nutrients every time you watered. Perhaps someone else has more experience with inside kept bananas and could pitch in here. By the way, the Ensete went from a two foot plant to almost 8 ft in what was a rather poor growing year last year, so it was happy in my setting. Good luck!
