No, the plant does not produce CBN directly, rather it is a degradation product formed by other Cannabinoids aging with storage.
As for picking early to change the Cannabinoid ratios, have you done this? I have many time and the ratio is pretty much fixed throughout flowering all that changes are the absolute amounts, the ratio remains constant, the terpenoids do change with different terpenoids peaking in maximum amounts at different times of maturation dependent on the terpenoid.
-SamS
This is the only mention I've been able to find about how terpenoids change as the plant matures. It's not much and I'm interested to know more.
Is there a general pattern in which terpenoids mature? Does anyone know? Is there research about this?