On a plate, evenly season roast with salt and pepper. Be sure to get all sides of the roast and massage seasonings into the meat. Allow to sit and marinate for 20 minutes while you prep the other ingredients.
In a bowl, mix together tomato paste and water, then set aside.
In a 6-quart slow cooker, add carrot, celery, onion, garlic, thyme, rosemary, and potatoes. Mix.
Drain any liquid from the marinating roast into the slow cooker, pouring evenly over the vegetables. Then pour in tomato-water mixture evenly on top as well.
