That's basically it. The basic concept is to plant your potatoes in the base tire and as it grows cover it with straw and continue to stack tires.
I started off with two pounds of potato sets. The morning before planting I cut them into pieces with a sprout or two on each piece and set them out to dry a bit.
After I had prepared the area by pulling grass and setting the first layer of tire, then I partially filled three of the tires with the soil and manure. The other two I left empty wanting to try growing the potatoes with no dirt at all. I set the potato pieces in the first three tires down in the soil and covered them lightly then placed a layer of clean dry straw over them. The other two tires I filled half way with straw, placed the potatoes and covered with more straw. Then after a good soaking with the garden hose all that was left to do was wait.
About a week or so later BAM....those little guys in the first three tires were up and growing. The others were slow going but a few days later all five tires were filled with beautiful little potato plants. The key is not to expose the root or spuds to light by keeping them covered with straw. Similar to the old row planting method and building up the sides of the rows with straw as the plant grew. The extra perk with the tires is they act as a hot bed, extend your growing season, grow vertically and make harvesting super easy. Just knock the pile over and pick nice clean potatoes!
Now as they've grown I've been stacking tires and filling them with only straw, watering when it doesn't rain and watching for critters. So far so good. Will we be successful and have tons of home grown red potatoes?
I'll keep y'all updated with our progress. Not really sure how long this takes but that's why it's an experiment. Of all the stuff I've read on it, no one really showed the end product. You can get your tires free most places considering they usually charge to dispose of them so your saving the tire guys money. Sounds like a win win situation!