Question
I live in Louisville KY and have been doing tropical outdoor displays for sometime. I manly use Bananas,cannas and Colocasias or other aroids. I really have no idea what I should be using on my plants to produce the best growth. In years past I use epson salt and 20-20-20. But I am interested in pushing the plants even more sense my season is shorter than most. These plants once growing seem to handle just about anything I put on them. I water almost every night and the soil has been enriched with manure and compost. One of my questions is what kind of numbers should I be looking for on my fertilizers and how much can I put on them.  
In the past I have grown a banana from 3 foot to over 18 feet in 5 months and hope to do acomplish similar feats again. THANKS  

Answer
It sounds like you are doing everything correctly.

A good deep amended organic soil, such as those you have created with manure and compost is the number 1 item you can do. Then using a balanced fertilizer such as 10-10-10, 20-20-20, etc is also excellent. Epsom salt is really only magnesium it is good for, which an all purpose fertilizer such as 20-20-20 should have (Peters). However, used in moderateration it does no harm (just remember that it is a salt and too much can kill plants). Dilute well, and water in with plenty of water. Generally, all the plants mentioned are heavy eaters and monthly applications are fine.

In hot summer months, both bananas and colocasia esculenta transpire lots of water, so watering frequently is a good idea. I am not sure you need to water daily, but if you can - and if you have had good results - I will only encourage you to continue. Also remember to mulch well around the plants.

Besides giving all these plants plenty of sun, you can start them off in a greenhouse to get an early start. But it sounds like you are already doing as much as you can.