Optimum Size Pot.

I know it's dependent on a few things but what do you folks consider to be the optimum size pot for the average 12 to 16 week soil grow. I've never had a plant so root bound it cried. Yes I've had them so bound up I had to water everyday but riddle me this... When is big enough big enough. The reason I ask is that I have 20 fresh five gallon buckets and I plan on cutting them down to size to save on height. I've got a low ceiling space and whacking a bucket in half will give me another 10 inches but how low can you go?? ty

i grow in 6 inch clay pots

Wow mc.. 6 inch clays? I do like clay pots. Plants really do seem to thrive in them. It's like they breath. They're the original air pots. 6 inch though eh? How many do you run and under what light?

1ltr of pot for every week of plant life. I think that's a rough rule of thumb taken from one of Jorge Cervantes books. Doesn't hurt to go a bit bigger.

you dont have to cut them down. just dont fill them up all the way. if your soil is at 8" it doesnt matter if the container goes up to 12-14 inches

One way for you to find this out for yourself is to experiment yourself with this idea. i remember in school being taught that the rootsystems area they cover of some trees can triple whats in the canopies that you see above ground............so if i were to cling to that mantra id want 100 gallon smart pots outdoors with an ornery old viet vet watchin them, sorry im medictaed atm.

Your right dict but I have a hot knive and I sorta want to use it. I'm not sure I want the plant/soil level to be that deep into the bucket anyway. It would make the girls more difficult to lst and tend.
Being pot bound is not an issue with annuals I don't think as long as they get sufficient h2o and nutes. It sounds like the rule of thumb is sumpin I can work with Corey. That basically puts me right at or about 3 gallons. Maybe I'll give it a whirl mango. I've seem some impressive solo cup ventures. I've also seen a pretty BIG plant coming out of one of those little single rose holders. Rock on.