THCa flower has become a sought-after product for cannabis enthusiasts and medical patients alike, but how is it made? In this guide, we'll delve into the fascinating world of THCa flower and explore how it’s cultivated and processed. THCa, or tetrahydrocannabinolic acid, is the precursor to THC, the compound responsible for the psychoactive effects of cannabis. When THCa is exposed to heat through vaping, smoking, or cooking, it transforms into THC.