I have been growing potatoes in containers. This will be my third or fourth attempt. All previous attempts produces string roots and no tubers. I am growing in two recycled water butts and two tyre towers. The plants look wonderfull, masses of foliage but don't know whether there's anything underneath. The tallest plant is currently around 5 feet. I am expecting the tyre towers to reach at least five feet before they mature. Will let you know the results (if any).