Sweet potatoes are grown from slips, which are also known as vine cuttings. Like other potatoes, the slips are created by allowing the sweet potato tuber to sprout. Once the slips have reached 12 to 16 inches long, they are twisted from the tuber and either placed in water or planted in the garden to produce roots and later sweet potato tubers.
Pick a sweet potato that will easily slide into a wide-mouth jar or vase.
Cut the sweet potato in half across the middle.
Place a toothpick approximately 1 inch above the cut portion of the potato in three or four places to create a stable holder.
Fill a wide-mouth jar or vase with water.
Set the potato on the top of the vase or jar, allowing the toothpicks to hold the top of the sweet potato above the water level. The lower inch of the sweet potato should be submerged in the water in the vase.
Keep the jar or vase full of water. You will see the potato begin to sprout vines within seven to 14 days. Allow the vines to grow until they reach 12 inches or longer.
Grasp the sweet potato vine at the base where it joins the tuber. Twist gently to remove the vine from the tuber.
Place the vine in a separate jar or vase of water and allow it to root. This may take seven to 10 days. Alternatively, you can plant the vines directly into a prepared garden space.