An alternative way of growing potatoes where you do not have to earth them up (adding soil as the potatoes grow), is to grow them through black plastic. We lay down a layer of black plastic over our prepped bed (and over our irrigation lines) first. Then we cut little cross hatches into the plastic where we want our tuber to go. We can push the seed tuber into the cross hatch "hole" a good four inches into the soil. A couple of weeks later, depending on the weather, the potato will sprout and grow right up through the hole in the plastic. The black keeps the forming tubers from turning green. This method is also great for trying to grow potatoes in colder weather.
Photo courtesy of Suzie Andersen