Sweet potatoes are grown from plants, not seeds or bulbs.
You can purchase sweet potato plants at a garden center or online.
You can also grow your own plants.
How To Grow Sweet Potato Plants
1. Get a firm healthy sweet potato. If the sweet potato is starting to sprout, you have a head start.
Assume that most grocery store sweet potatoes are treated with an anti-sprouting chemical. Look for organic sweet potatoes or get from a gardening friend. My sweet potatoes came from my mom and a friend. I don't know what variety they are but both of them had excellent sweet potato crops last year and they kept very well all winter. Sounds like traits I want to encourage!
2. Place the sweet potato in a jar of water. You want to submerse most of the sweet potato while allowing a couple inches above water. One of my sweet potatoes was so large it couldn't fit well in the jar. Change the water occasionally to keep from molding. Place in sunlight. Soon the sweet potato will send out sprouts, or slips.
3. When the sprouts are four to five inches long, pull them off the sweet potato. The sweet potato will grow more sprouts.
4. Place the sprouts in water. You can place a bunch of sprouts in the same jar. They will quickly grow roots.
5. When the sprout is well rooted, plant in a hill of soil about ten inches high. Wait until the soil is warm. In our area, this is in June.Sometimes we plant them after we pull out the peas to maximize our garden space.
Keep the plants well watered while the roots are being established. We like to mulch the hill to keep back the weeds as the sweet potato grows.
While sweet potatoes can't be planted too early because they hate cold weather, they also can't be planted too late. My aunt, who has grown sweet potatoes to sell for years, says to plant on July 4 at the very latest in our area of PA. Sweet potatoes need several months of growing time before the first frost to form tubers.
Some years I have started my sweet potato plants too late. They need adequate time to root before being planted outside. I have found that the beginning of March is a good time to start my plants.
For more information and recipes for sweet potatoes see the Grow, Eat, Enjoy Sweet Potatoes.
For general gardening information and our Pennsyvania gardening experiences see the Gardening Page.