When i had two allotments a couple of guysthere put the spuds in flat ground , never earthing them up . Ok ... the soil was a good quality built black loam soil and drainage was good . Their spuds were as good as anyone elses.
One thing for you spud planters if you don't know ......... it's best to grow spuds in rows north to south ( lot of other crops as well " . For the sun has the longest time to warm the soil on each side of the plant .
If you run them east to west the sun only warms the south side