I have a bell pepper in a 5 gal container. Was doing great, then suddenly stopped growing and older leaves "turned over".
Benton County Arkansas
Not for sure what you mean by leaves turned over. But in a container most times it is a water issue. To much or not enough. Make sure the pot has drain holes. Container plants also run out of nutrients so keep up a good fertilization schedule. That is the best I can do without seeing the plant. Let me know if you have follow up questions. Dennis