There is no definitive answer to this question, as different strains have different genetic potentials and environmental factors can also affect THC production. However, some experts believe that there is a theoretical limit to how much THC cannabis plants can produce, which is around 35% to 40%. This is because THC is synthesized from a precursor molecule called CBGA (cannabigerolic acid), which is also the precursor for other cannabinoids such as CBD and CBC. Therefore, there is a trade-off between the production of different cannabinoids, and if one increases, the others decrease.