I'm growing cascades and chinook. I'm using 18 gallon containers (tubs you'd find at WalMart), one rhizome to a container. So far, so good.
[Edit: I drilled about 20 half-inch holes in the bottom of each one. Used 3 cubic feet of potting soil in each tub. Miracle-Gro diluted to quarter strength whenever the green color starts to pale at all...have only had to fertilize once so far.]