I see you say...
tried the caged method a couple of times the suggestion was to build up the mulch around the 'tater plant as it grew but then mulch doesn't drain like soil does so it contained a lot of moisture, why we gardeners use it in our gardens to that degree.
but have found the current method we use to be far more productive our return is in the 6-6:1 ratio which for the little work invested is pretty good. so check our instant potato patch presentation see what you think, we are lovers of the manicured lawn so we pick a patch of grass that won't do much over winter and go from there, harvest is usually the next spring early summer for our growing season.
the grass soon comes back.
Where are you based gardenlen?
On the 18th; 19th & 20th of July, we experienced 3 frost mornings, the 2 days (18th & 20th) where White Frosts of very noticable proportions estimate ground temp' -4c