Every year about this time gardeners start inflicting all manner of experiments upon the humble spud. We drop them into burlap sacks, grow pots, wood towers, mesh towers, tire towers, garbage cans, straw bales and more. We attempt the Square Foot method, the Ruth Stout method, the Hilled Row Method, the Plastic Mulch Method.

The goal with these various growing methods is always the same: maximum possible yield of clean, unblemished potatoes in a minimum of space. To achieve this ideal, potatoes need moist, rich, acidic soil under the seed spud and loose, dryish, lightweight soil or other matter above, where the vine will grow and new tubers will form. These conditions are easily created in container culture, and bins and cages give the added advantage of dead-simple harvest. Once the vines die back, you tip-and-pick.

More here: http://www.nwedible.com/2013/04/how-to-make-a-heavy-duty-potato-cage.html