Seed potatoes are small potatoes that have growing eyes on them. While some seed potatoes are planted whole, most require cutting up, and the resulting pieces are then planted. A single seed potato may grow into three or more plants with this method.
Cut seed potatoes into pieces that are 1.5 to 2 oz. each, making sure each seed piece has at least one good growing eye or bud on it. Set the pieces cut-side down on a tray and allow the edges to dry overnight. This prevents rot after planting.
Choose a well-draining garden bed in full sun for planting. Lay a 3-inch layer of mature compost over the garden bed and till it in with a power tiller to a depth of 18 inches.
Sow seed pieces 3 inches deep with the eye facing up. Space plants 12 inches apart in rows that are 24 inches apart.
Water as necessary to keep the bed moist but not soaking wet. Once seedlings emerge, lay a 1-inch layer of organic mulch over the bed to help preserve soil moisture.
Use a hoe to pull soil from between the rows toward the seedlings. Cover the stem as it grows so only the leaves emerge from the soil. Gradually build the soil up to a height of 6 inches. This protects the potatoes forming near the soil surface from burning in the sun.
Harvest in late summer or early fall after the plant has begun to die back. Overturn the soil with a spading fork to reveal the potatoes, being careful not to damage the potatoes as you turn them out of the soil