XJ-13 (Sativa) - Signature Cultivar XJ-13 is the cultivar that built THC Design. A cross between Jack Herer and G13 Haze, XJ-13 is a Sativa-dominant flower that balances high levels of THC with Terpinolene, Caryophyllene, and Ocimene terpenes, making it a great choice for daytime productivity without the raciness that is found in a lot of Sativa-leaning strains.