Sweet potato vines are easy to start at home with nothing more than a normal sweet potato and a few household materials that you may already have on hand. Once the sweet potato vine is growing well, it can be transplanted outdoors in the garden or left in its container for indoor growing. The vine can be treated as a houseplant or planted to create more sweet potatoes for harvesting and eating.
Stick three toothpicks into the side of the sweet potato, about a third of the way down from the top of the larger, rounder end. Space the toothpicks equally apart from one another. They will form a support to hold the potato in its jar.
Fill a clear glass jar about halfway full with water. Place the sweet potato in the jar with the narrow end dipping into the water and the toothpicks resting on the rim of the jar. The larger end of the potato should be sticking up out of the jar.
Place the jar in a bright, warm, sunny window and wait for vines to appear. It will take as long as 10 days for new roots to begin growing. Once the bottom of the jar is filled with roots, the sweet potato vine may be transplanted.
Prune the vines that grow from the top of the sweet potato if they become excessively long or unkempt. Snip off any excess growth as necessary. You may also allow the vines to trail over the jar.
Transplant the sweet potato vine outdoors in late spring to produce more sweet potatoes in the fall. Plant in an area that receives full sun and has well-drained soil. The top third of the sweet potato should be above the ground. Stem and leaf buds will soon appear, followed by flowers.