6 to 12 inches
Sow the seed pieces directly outside or in a pot when the daytime temperatures reach 60 degrees F. Plant small seed potatoes (or pieces of larger seed potatoes) with 2 to 3 eyes in each piece. Plant them 3 to 5 inches deep and 6 to 12 inches apart. Water as needed to keep the soil damp but not flooded. When the plant is about 6 inches tall, pile a few inches of soil or clean straw around the main stem to form a hill. Add to the hill several times throughout the season.
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