Grape Pie x Sour Apple THC: 18.02% Delta 9- THC: 0.084% Boston Runtz is a THCA- rich strain of cannabis that is a cross between Grape Pie and Sour Apple. It is known for its sweet and fruity flavors reminiscent of the classic candy, Runts. As with other strains of cannabis, Boston Runtz also contains other cannabinoids, such as CBD (cannabidiol), as well as terpenes, which are compounds that give the plant its characteristic aroma and flavor.