Cut carrots in half lengthwise and then into 2" pieces. Place in a 5 qt. slow cooker. Add water, soup mix, garlic and celery seed. Cut roast in half; place over carrot mixture. Sprinkle with salt and pepper. Coveer and cook on HIGH for 2 hrs.
Reduce heat to LOW; cook for 4 hrs. Add cabbage; cook 2 hrs. longer or until the cabbage is tender and a meat thermometer reads 160*. Remove meat and vegeetables to a serving plate; keep warm. If desired, thicken pan drippings for gravy and serve with the roast.