I'd avoid tomato or pepper
I ran out of chow once and fed the worms tomato and bell pepper until I could get more chow. It makes their poop very, very wet, and makes a horrible mess. It really is all about the heat. But I did get a shipment once where the worms didn't grown, and then they died. It was inexplicable, in that there was nothing visually wrong. But when I told the vendor, they replaces it, so it must happen on occassion.