I do that sometimes too, lol!
Cause I got toooo many things to try to remember!
Here's what I've learned so far.
1. Pot size. If it's a pup then the pup should be about 1/4 to 1/2 inch wide and about 3-6 inches tall or more. That size pup needs a 6-8 inch wide pot. When it's about 2-3 feet tall, it needs a pot about 1 1/2 feet wide. Oh, and about as deep as it is wide cause most banana trees have shallow roots. Except Ice Cream bananas and they have deep roots.
2. Snow. I love snow but banana plants dont!
They like to be about 50*F or more all the time. Also, if it's like 50-60*F, they dont want any water or the corm (the part that's underground) will turn soft and start rotting and kill it.
3. Watering. If it's summer, they need lots of water then they needa dry up totally before they get lots of water again. They needa be dry for a whole day.
If it's winter, they needa be inside and warm. But even if it's really warm inside, they grow a lot slower in the winter. Only give them a little water about every 3-4 weeks. Oh, and no plant food in the winter.
4. Feeding. They only need a little phosphate but lots of Potash (more Potash than Nitrogen). So the NPK should be something like 2-1-3. Two good ferts are Scotts Miracle Gro For Fruits (16-8-24) and Grow More (20-5-30).
They like lots of ferts sprinkled around them but not on the base of the tree. That should happen once every 3 weeks in the summer.
5. Light. Most banana trees love tons of light. But dwarf Cavendish doesn't like it as much and needs to be near a shady area. Ice Cream bananas light tons of light and high temps, even 100*F or more.
6. Buying pups online. There's sites online where you can buy them BUT be careful! Most sites are selling clones they make with tissue cultures. NOT GOOD. The clones are tiny and dont survive shipping very well. And sometimes they ship them too wet and they rot. It's really tuff to buy one online and get one that will survive. I only have 2 that I bought online and they're both dead.
The best way to get good pups is from friends or at a farmer's market or a hardware store that sells plants. I got all the trees that I have (and are still alive) that way!
7. Disease. If the leaves ever start looking yellow or brown, spray them with a copper fungicide. That will cure almost any banana disease!
That's all I can think of right now and I hope that helps!
If you have any more questions, ask!