My mother had a bowel perforation during a barium x-ray for diverticulitis. She ended up having surgery and a small part of her bowel removed. She has not followed any kind of anti-diverticulitis diet as she believes all the disease was cut out. If you had some at one time are you not prone to have it again?
Stay away from all seeds especially tomato. When they say seeds they mean all of them take it from someone who thought that maybe one wouldnt hurt. Read some of our stories under problems after a bowel resection if you want to see what a possible outcome could be.
I don't know about tomato seeds, but the rest of that is correct: If you have diverticulosis, you should avoid seeds and nuts, as these may not properly digest and lodge in the diverticulum, causing diverticulitis.