Italian Meat Sauce

1 1/2 cups chopped onion
1 1/2 pounds ground chuck, browned
1 (28 ounce) can tomatoes
2 (6 ounce) cans tomato paste
3 teaspoons dried oregano leaves
1/4 teaspoon dried thyme leaves
1 bay leaf
2 stalks chopped celery, with tops
2 cloves garlic
2 teaspoons salt

Put all ingredients into crockpot; stir thoroughly. Cover and cook on LOW for 10 to 12 hours or on HIGH for 3 to 5 hours.