How much mediam is needed?

I'm thinking my flowering room is going to accomidate about 50 plants using my kooky logic, so I wanted to know is what size containers should I use if I want to grow plants to 4 to 5 ft. Is a 3 gallon enough?

id go for 5gal at the least.

In soil 4-5gal would give better yeilds, but 3gal coco works really well. Old school rule of 1gal soil per foot of plant, but coco gets away with less.
My first big setup I tried to fit more in there by using smaller containers, but I learned give them the root space and you'll be rewarded.

A gallon a foot is a good rule.

Gallon a foot. Makes good sense. Thanks Guys.