castor oil for the scalp.
grease doesnt grow your hair but maybe helps you keep what you have. IMO, though, petroleum based products, aka grease, are no superior to preventing breakage than things like profective breakfree, carrot oil, carol's daughter products, or kemi shea pomade, which are mineral and petroleum oil free.
when i used grease i used bb super gro and retained length. by comparision though, my hair felt less moisturized.