Plants and THC

[Likes to build bongs]

When do plants start to get thc?
and
What is the reason the plant has the chemical THC? Is like for defence or does it make it stronger or something?

[HARDDON]

A complex, thorough insight into THC can be found here:

http://www.hempfood.com/IHA/iha01201.html

and an even better one here:

http://cannabisculture.com/articles/2159.html

[42h0man]

damn HARDDON, your just a wealth of knowage.. nice links