Biggest indoor plant I have seen a picture of was the Purple Cindy grown by Earl in his aeroshuttle or whatever he calls it. It was about 8' guessing from the picture. Its posted alot of places so a google would probably find it really easy. I have yet to see a repeat of that grow though. Purple Cindy is Purple Oregan Thai (chococate thai x one of the south american sativas) x c99.