Depends on the variety but I seldom mound soil up more than a foot and then straw for another 6"-1 foot. This is for in-ground ones. In a bin you may want to go a bit higher but not much - say another 6" more.

Dave

I think that everyone has an idea of what they want to do when mounding potatos. I probably mound them excessively, but I mound them about 30" high. The plants (Kennebecs) grow to about 4' tall and I get some real walloper potatos under there. I did not grow potatos this year. We had such an abundance of them last year that I canned a lot of them and want to use those up. We still have about 20 quarts of potatos left. Well now I lied. I do have two mounds over in the flower bed. I just used store potatos that had sprouted. These I haven't mounded but maybe a foot. Not enough dirt surronding them to mound without digging up some perennials.

Oh and when the get to blooming I just take and lop off all the branches and blossoms and leave about 8 to 10" of plant left showing. That seems to make really big potatos.

Helen

The point in hilling potato is to burry more of the stems so that tubers can grow on them.
Most potaoes (tubers) will grow just above the main root, i.e. the seed, to a hight of about one foot above it.
So, too much hilling is not going to make the potato plant to grow more tubers. I think that the top of hill should be about 18" from the seed. 18" is more than enough stem on which tubers can grow. Also, in my experienc, nothing can beat good fluffy soil rich in organic mater/compost. just add a thick layer of mulch after final hilling. This will keep soil from drying up too quickly.