I remixed the modular tower from https://www.thingiverse.com/thing:3405964 and combined it with the improved locking ring from https://www.thingiverse.com/thing:4965368/files. For the lid to the 5 gallon Lowes bucket, I used https://www.thingiverse.com/thing:4580194  I need the tower to be as stable as possible since it was going to an elementary school for kids to grow their own plants. 

I used 4 walls with 25% infill. everything came out nicely. I believe an Ender 3 can fit all the parts on it. I am not sure about the planter section but everything will fit.