Growing sweet potato plants the old-fashioned way takes a bit of effort, but it can be a fun experiment. Sweet potato plants are usually grown from slips, which are available at gardening centers. Years ago, however, gardeners had to start their own slips indoors. This method does require some advance preparation. Sweet potato slips need to be planted in the ground about two weeks after the final frost, which means that you will need to start the slips about four to six weeks prior to the projected final frost date.
Purchase untreated sweet potatoes or use some from your previous crop. Untreated sweet potatoes are different from most sweet potatoes found in the stores because they are not treated with chemicals and wax to keep eyes from forming.
Fill a jar about halfway with water. Slide the sweet potato, eye-end-up, into the jar until the bottom third is submerged. Poke two toothpicks into the sides of the sweet potato to suspend the potato in the jar.
Set the jar in a warm, sunny spot for about three weeks, or until sprouts start to form in the top. Refill the water as necessary; the sweet potato will drink more as the sprouts become taller.
Harvest the sprouts when they are about 6 inches long. To do this, grasp the stem and carefully twist it off of the potato. Place each stem cut side down in a shallow bowl filled with about 1 inch water. Roots will emerge from the bottom of the stem. When they are about 1 inch long, the slip is ready to plant.
Growing Sweet Potatoes
Loosen the dirt in the garden plot with a gardening rake. Sweet potato plants require well-aerated soil to grow because the roots need to extend deep into the dirt.
Rake the soil into 8-inch-tall, raised ridges. Allow at least 3 to 4 feet between raised rows, because the plants spread out as they grow. Dig holes that are 4 to 5 inches deep and 12 to 18 inches apart in the top of the ridges.
Place the slips, roots down, in individual holes and fill the holes with dirt. Water the slips thoroughly, soaking the soil but not eroding the dirt mounds. Water the slips every day for the first week, every other day in the second week and every third day in the third week. Cut back to once a week after that and keep up that schedule until the harvest.
Stop watering the sweet potatoes about three to four weeks before harvesting them in late summer or early fall. Dig up the potatoes with a spading fork, being careful not to damage their flesh. Store the sweet potatoes in a dark, cool place.
About this Author
Katie Leigh is a freelance writer and editor based in Chicago. A Loyola University New Orleans graduate with a Bachelor's degree in communications, Leigh has worked as a copy editor, page designer and reporter for several daily newspapers and specialty publications since 2005.