Grow potatoes in a container by filling a container, such as a trash bag or garbage can, with potting soil along with slow-release fertilizer and compost. Plant the seed potatoes, and place the container in an area with up to eight hours of sunlight per day.
First, prepare the soil by combining 4 to 6 inches of potting soil with compost or slow-release fertilizer. Pour the soil in the container of choice. Prepare the seed potatoes for planting by cutting a sprouting potato into pieces, with each piece containing at least two eyes each, and planting them immediately in the soil. Very small potatoes can be planted whole. Space four potatoes or pieces of potatoes evenly in a 20-square-inch space. Cover the potatoes with only a few inches of soil.
Water the potatoes well and regularly, making sure that the soil remains moist at all times. Once the seedlings reach 6 inches tall, add more soil and compost to the container, and continue to do so to prevent the potatoes from growing out of the soil and getting sun-scorched. Harvest the potatoes once the plants blossom or the greenery yellows and dies. Keep any smaller potatoes for seeding the next year.