[garyjr]

"I don't think there's much connection between pruning and BER, never been a problem for me pruning to one stem. Water regularly, or install some automated method. Dry farming is not a good idea at all in containers, never let them wilt even a bit." -zipcode

This is good advice. Many soil growers wait until they see signs of wilting then water. If you do that with containers it is very likely that it is too late and you are inviting BER. I have installed a simple drip system this year to water my patio planters. If you still have a problem with it then consider growing more determinates.. Not sure why but they seem more resistant to BER in containers than the indeterminates that I have grown.