Cover your seed pieces with three to four inches of soil to begin, adding another three to four inches of soil when you see the sprouts emerging about two weeks after planting. Another hilling should be done when the plant stems reach about eight inches tall, covering the stem about halfway with soil. It is better to have broad, flattened hills that tall, peaked hills, so pull soil from between the rows to broaden the hills if necessary. This is important because you want the potato plant to send its stolons, or undergr...

Cover your seed pieces with three to four inches of soil to begin, adding another three to four inches of soil when you see the sprouts emerging about two weeks after planting. Another hilling should be done when the plant stems reach about eight inches tall, covering the stem about halfway with soil. It is better to have broad, flattened hills that tall, peaked hills, so pull soil from between the rows to broaden the hills if necessary. This is important because you want the potato plant to send its stolons, or underground stems, evenly about the hill instead of remaining close to the main stem. Tubers set at the distal ends of stolons, and you want there to be plenty of soil to cover the forming potatoes so they don't push out of the hill. If the tubers are exposed to light, it triggers the production of chlorophyll in exposed areas. Chlorophyll is associated with the formation of solanine, a bitter and toxic (in significant quantities) glycoalkaloid that is heat stable and minimally impacted by cooking. So, keep those tubers covered in soil!