Combine Liquid Ingredients: Add the red wine and beef stock to the crockpot.
Add the Veggies: Add the carrots, onion, and celery. You can add potatoes too, which I've done with other crockpot recipes. Make sure to add evenly.
Season the Meat: Rub the olive oil over the meat and season with the salt, pepper, garlic powder.
Place Meat (Fat side towards vegetables) in the Pot.
Turn on the low setting and cook until the inner temperature is 135 for medium-rare. With a prime rib between 4-5 pounds, this will take between 4-5 hours.
After the prime rib has an inner temperature of 135, it cooks for one additional hour.