Quote Originally Posted by Opie Yutts
There's no way you need 25 or 30 gallons for one plant. Sure the bigger the better, but there's a point where it gets a little ridiculous. Right now, using an Emily's Garden and a DIY Emily's Garden, I'm growing 9 plants in 3 gallons, or 6 plants in 2 gallons, whichever sounds the coolest. I have to add nutes every 4 days, at which point they are getting close to running dry. The good part about that is it's a complete reservoir change 7 times each month instead of 1. I've grown big beautiful crops using this method.
I ran a 5 gallon bucket DWC system for a single plant, the rootball took up the whole bucket within 6 weeks from a seed. I am sure given enough lumens I could easily fill a 25 gallon bucket with roots by the time flowering was done and that would make for a huge plant.