How do I prepare soil for planting potatoes in a planter?

www.hometalk.com/diy/grow/potatoes/planting-white-potatoes-in-a-tub-or-bucket-138568

Plant your potatoes after all danger of frost has passed. Make a free draining soil mixture and mix in a handful of time-release fertilizer. Fill the container 4 inches deep with previously moistened medium. Cut the seed potatoes into 2-inch chunks that have several eyes on them. Small potatoes can be planted as they are. Plant the chunks 5 to 7 inches apart and cover them with 3 inches of moist soil. Cover container potatoes with more soil after they grow 7 inches and continue to cover the small plants until you reach the top of the bag. Container potatoes should be kept well watered but not soggy.

Good luck!