I was thinking of growing my plants upside down after hearing of much success regarding upside down tomato growing, and for some reason i began thinking of the benefits of growing underwater through veg. I know if the roots were constantly underwater the plant would die, but by keeping the plant upside down you can avoid this. With the plant underwater, 1 you could keep the plant cool and 2 you could give it alot more c02; since co2 disolves in water, you could enrich your plant with a c02 generator alot more effectively than in a grow cab. c02 is a huge contributing factor to growth according to what I've read.
I'll definitely be trying this the next time I have a plant in veg that I can take clones from. This is probablly going to sound really stupid to me in the morning, and I'm sorry if it does to you, but I wanted to hear other people thoughts before dismissing it. I realize this is kind of a foolish question, however unconventional thinking is what creates progress.