Spray a 6 quart crockpot/slow cooker with non-stick cooking spray. Place 1/2 of the chopped potatoes, sweet potatoes, onions, celery, and carrots into bottom of crockpot. Place seared roast on top of vegetables. Place remaining potatoes, sweet potatoes, onions, celery, and carrots on top of roast. Evenly place minced garlic all over the top of vegetables.