I,ve been growing close on eight years and never noticed the stems being hollow or not.
I have got a piece of bud infront of me and yes it is hollow ,hehe and i grew it hydoponicly.
But i haven,t got any soil grown bud so I can,t say , but i would bet that the stems have nothing to do with how it was grown.
Maybee it,s to d with breed of plant , I think that would be more phesable.
An ol wives tale that be i say.

Disco....