I have found that all nightshades do very well in acidic soil, So my potatoes this year, i did a layer of soil, layer of straw and a layer of mulch then pine needles, once through the pine I will cover with another 4 layers (of the same). I do, though, grow using the old tire stack method. This way the tires keep the soil warm and not much to harvesting other than pushing down the tire stack.