Runtz S1 is a cannabis strain that is described as a relaxing hybrid with a unique flavor profile, typically featuring notes of watermelon and diesel. It's also known for its attractive appearance, with flowers exhibiting blue and orange tones. In breeding terms, "S1" refers to the first selfed generation of a strain, meaning it's a product of self-pollination. This results in a strain that has been bred through self-pollination of the original female plant.