Grow sweet potato vines as an ornamental plant, indoor house plant, or to get a head start on your sweet potato crop. Sweet potatoes do best in warm-climate gardens. If you live in an area with a shorter gardening season due to cool weather, consider growing your vine as an indoor house plant. Starting a sweet potato vine makes a great winter project for both children and adults.
Purchase a sweet potato with numerous "eye" spouts. These are points on the potato from where a vine could sprout out. While supermarket potatoes are not ideal, since they have spent a lot of time in transit and on the shelf, they will work for growing a sweet potato vine.
Insert a toothpick about 1/3 of the way down the length of the potato, and push it in about 1 inch. Insert a second toothpick opposite the toothpick you just inserted, so the sweet potato has a toothpick handle on each side. Insert two more toothpicks at the same level on the front and back of the potato, so there are 4 toothpicks in the potato altogether.
Place the potato, pointed side down, into a mason jar. The toothpicks will hold the potato up so that the top third of the potato is out of the jar and the pointed side of the potato sits in the jar.
Fill the jar with water. Cover the entire inserted portion of the potato with water.
Set the potato in the jar in a sunny location. It needs the sun and warmth to thrive and grow. Vines with leaves begin to grow from the top of the potato in approximately two weeks, and roots will begin to sprout in the water at the bottom of the potato.
Add a pinch of fertilizer to the water every month. When the roots begin to take up a lot of room in the jar, it is time to decide what you are going to do with your sweet potato vine.
Plant the potato outside after all danger of frost has passed. This must be done by late May to enjoy a fall harvest. Or, if you wish to keep the vine as an indoor house plant, transplant the tuber and roots into a large pot with potting soil. Continue to fertilize once a month.