In the past when I've done this type of cook I would just dump everything in at the beginning and let it ride. The problem with that is - although the carrots, celery and onions can take it, the potatoes would get really soft and start to break up, the green peppers would basically vanish. So for this cook I decided to stager the vegetables by how long I think they needed to cook based upon a total cook time in the 4 hour range. Wow what a difference that makes. All the vegetables were cooked properly and nothing was mush. This was one of my best pot roast cooks to date. I will use the vegetable stager method from now on.