I recently saw a field planted with potatoes. The field was beautifully carved into parallel ridges with furrows in between. I've looked with Google to find out why this is done. The answer seems to be that the potatoes are planted in the furrows so that the soil of the ridges can be used to "earth up" the potatoes, promoting a greater crop. However, the sprouts I could see were coming out of the ridges, not the furrows. Any potato farmers out there? Can you explain?
If you could see the 'sprouts' then the plants had already been "earthed up" with the soil of what were the ridges. Where the ridges were will now appear to be furrows between the rows.
Etch is right. Spuds need to be 'earthed up' as they grow to prevent them becoming green. If you can just see the tops then they have been earthed up.
This year we have resorted to 'potato bags' and the amount of soil used to earth up is very obvious - more so than out in the fields.