Humidity also plays a role in plant resin production. Although some potent equatorial strains do seem to occur in high humidity areas, most high-test land races have evolved in drier areas, like Afghanistan. The aridity of the areas of Afghanistan where Indica strains have evolved is quite apparent by the trait of large dense flower clusters. This would only be an advantage in an area of low humidity, as flowers will mold in anything more.2
There are many examples of non-cannabis plants producing resins in order to protect themselves from drying out. The waxy coating on cacti and other succulent plants is a prime example.3
marijuana flowered in humid conditions will often have a longer stalk on the glandular trichome than the same strain grown in drier conditions. While this may give the appearance of being very crystallized, it will likely contain less THC than the same plant grown in a drier environment. Another problem with longer trichome stalks is that the gland heads are more likely to break off during handling.
