Sometimes, even with the best intentions, seed potatoes begin to sprout because you haven't been able to get them in the ground. This can be due to weather conditions or simply because you haven't readied the garden space in time. Seed potatoes go through three stages: young seed, middle aged and old. All can be planted, although the older the seed, the less actual plant you will have and the fewer tubers the plant will make.
Cut large seed potatoes into pieces approximately the size of one large hen egg. Ensure that each piece has at least one sprouted eye. Smaller potatoes can be planted whole.
Dig a trench in the prepared garden space 6 inches deep. If you plan to plant more than one row, space subsequent rows 2 feet apart.
Break off all but one long, stringy potato sprout from the seed potato pieces. If the sprouts are still small, there is no need to break them off.
Space the seed potatoes 10 to 12 inches apart in the trench. With a long stringy sprout, lay the sprout horizontally in the row, to be completely covered.
Cover the seed potatoes with at least 4 inches of soil. Do not water until the sprouts emerge from the soil.