Hello ladies and gents:
I put a post in the Iris section and thought I would have a look see.
Anyway; I have been planting potatoes for forty years, after watching dad for a couple of decades.
I am in Mn and have two gardens, one in slight acidic black-gumbo and the other in sandy clay.
I have tried every method using garden soil I have ever read.
No raised bed, bag etc. as I have no reason to.
My father and I both tried the laying on ground and covering with mulch. It is a back saver at harvest time but, for me yields were lower and the potatoes were smaller. I like french-fries so I like LARGE potatoes.
The past two years I have been burying deep (my dads standard was eight inches or the depth of a sand shovel) but even that deep you would have some popping out of the ground.
The past two years I have put them from twelve to fourteen inches down. Oddly I still had some pop out of the ground even though I also put about sixteen inches of leaves I had used to cover the roses in winter over the hills after planting.
I have never hilled potatoes because I have used mulch for years but dad used to do that .
I put about three yards of sheep manure on the garden every seven or so years, and in a hit-miss method, fertilize on occasion.
Last year I turned the manure in in the spring, after it sat on the garden all winter.
Out of approx., I never counted eighty hills, plus or minus a dozen, in the two gardens I got seven grocery store tote boxes very full.
I planted seven types of potatoes and a row or so of left overs from the year before.
I found that planting that deep, it will produce potatoes all the way to the bottom in abundance. I space plants and rows about sixteen inches apart as I loathe spiking when I dig but even at that I still sliced over a half-dozen in half when I dug them up. I dig with a shovel.
In the sandy clay I can dig them by hand if I want but in the black-gumbo it is work especially as we had a nice wet fall and black-gumbo is like digging in clay without the gummyness. I would dig one shovel depth and out came a few standard size potatoes but I thought that as I planted them deep to go down another shovel depth. The best way to describe what it is like digging in that dirt when it is a bit moist. The average dirt chunk was the size of a bowling ball with some fifty percent bigger. As this soil has been worked for seventy five years it has good spot and miserable spot to work with.
Anyway.
To even my amazement, the biggest were the deepest. Sometimes I would take a big clump of dirt, where there was no sign of containing a potato, drop it on the ground and out would roll three or four large potatoes.
Outside of when I broke fresh soil in the sandy-clay area, this was the best crop I ever had in forty years.
Sadly my family is now down to where half that would have been more than enough so I had three left over at planting time.
For the first time in my life I did not buy any potatoes for planting and after the garden was over full of new planting still had to toss a fair number into the compost bin.
I put whole potatoes in each hill, some very large and in a few put two or three small ones.
From my decades of experience I have found that deep planting with thick mulch on top works best. It keeps the ground moist in dry spells and reduces work, except for planting or digging, as far as taking care of them during the growing season.
I have planted several dozen varieties and the All-Blue ones were without a doubt the best tasting, while Victoria produced the greatest yield, even better than the normal standard Kennebec.
But, I want to do this right so
Excellent!! 
