This indica-dominant hybrid has potentially massive THC levels, upwards of 24%. That makes it a favorite of medical marijuana patients seeking treatment for their stress and chronic pain. Black Jack has a sativa/indica ratio of 30:70, a result of its Black Domina and Jack Herer genetics. To be clear, there are actually two strains called Black Jack, including a second hybrid that descends from Black Domina and a European local known as Jock Horror. The latter strain is known as Blackjack, though it’s quite similar to the original Black Jack. CBD levels are low in Black Jack, so this strain isn’t recommended for seizure disorder.