The plant's actual functioning roots will grow downward and outward from the seed potato, potentially reaching a depth of as much as 18 inches, according to North Dakota State's extension service. In between is the area where the actual potato tubers grow on specialized roots.

Why are my potatoes growing above ground?

Potatoes grow underground on a special stem called a 'stolon'. The potato stems above ground have attractive but non-edible flowers. ... A potato field needs to be kept hydrated at all times. Potatoes can survive drought but do not produce as many potatoes if they do survive.

Do potatoes grow vertically?

In a vertical-growing system, you must provide enough soil for the vine to generate a sufficient lateral root system to produce a crop of potatoes. As the vine grows upwards, continue adding 3 or 4 inches of soil to the bin so that just the top leaves of the vine remain exposed.