Instead of seeds, potatoes are started from cut up potatoes. Each piece has a growing eye on it that turns into a new potato plant. Potatoes are rarely grown as transplants, as disturbing them damages the potatoes the plant is producing beneath the ground. If your gardening season is short or you just want to get a head start on your potatoes, you can grow transplants using an old English method of sprouting that is called chitting. This enables you to get the potato plants started four weeks earlier in spring than you normally would. Use early potato varieties to grow these transplants.
Cut apart the seed potatoes with a sharp knife into 1.5 inch cubes. Cut so each cube has one to two large buds or growing eyes on it.
Spread potatoes out on a tray so they aren't touching. Place them so the growing bud is facing up and the cut side is down.
Place the tray in a cool 55 degrees F room to sprout. Position them so they receive bright, indirect light from a window. Place a translucent shade over a window to diffuse the light if necessary.
Transplant potatoes outside once the sprouts are half an inch long, taking care not to break the sprouts when planting. Plant deep enough so that the top of the sprout is even with the soil surface.
Pull soil up around the stem of the potato plant to form a hill as it grows, so that the top leaves remain above the soil surface. More potatoes will be produced from the stem as you cover it in dirt.