Sweet potato plants are grown from rooted pieces of vine called slips. Growing slips is one of the easiest ways to propagate plants, making this project ideal for the beginning gardener. One sweet potato can produce enough slips to fill an entire garden row, so this is an economical project as well. Plan your project to begin about a month before growing season, and you can harvest baskets full of sweet potatoes in the fall.
Shop for your sweet potatoes in the organic produce aisle. Organic vegetables haven't been treated with chemicals, so they will be more likely to sprout. Choose a potato that already has some "eyes" on it if possible, which are buds of the slips that you will grow.
Push four toothpicks into the sides of the potato, one north, south, east and west. These toothpicks will hold the potato in place in the jar.
Fill a jar about 3/4 full of water. Place the toothpick-filled potato into the jar, with the pointed end down. Make sure that at least the top 1/3 of the potato is sticking up above the water.
Place the jar in a sunny location. Check the jar every day, and replace the water when needed to keep it at the same level. Your sweet potato will sprout in about two weeks, with white or pinkish growths growing out of the potato surface.
Turn the jar daily after the potato has begun to sprout, to make sure that each side gets the same amount of sun.
When the sprouts, or slips, are about 6 inches tall, use scissors or a sharp knife to cut them from the potato. These slips are what will be planted in your garden.
Fill peat pots with potting soil. Place one slip into each pot, making sure that the end that was closest to the potato is in the soil. Water thoroughly and keep in a sunny windowsill. In about two weeks, roots will begin to grow on your slips and more leave will appear. You may now plant them in the garden.