When & how deep

I'm no potato expert, as I don't bother with them these days, but I often wondered about the logic of earthing up. If they were planted at the correct depth but in a trench, which would then be filled as the greenery showed, would that work the same as earthing up. I always found my earthing up was never high enough to cover the spuds so I got green ones. I don't really need an answer, just musing.
As for chitting, I'm in the bung 'em in camp, what have you got to lose?