Starting Sweet Potatoes

Sweet potatoes are one of my favorite foods to eat and to grow. While most vegetables are grown from seeds, sweet potatoes are grown from rooted cuttings called slips. You can buy slips from many garden centers and from mail order sources, but starting them yourself is easy and economical and many gardeners prefer to go that route. All you need to get started is a sweet potato. You can use ones from the grocery, but you likely won’t know the variety. It’s better to start with a known variety and one that is suitable for your area. If you’ve grown them before, you can start with one from storage. If not, ask around and see if a friend or neighbor has one you can use.

There are several different ways to start the slips. One way is to cover the sweet potato with soil or sand in a container, and supply bottom heat until they start sprouting. The method I’m using is to suspend the sweet potato in water until it roots and starts sending out sprouts. Then I’ll twist off the sprouts and put them in water to form roots on them. At that point they are ready to set out, or if it’s not time to plant yet they can be potted up into individual containers.

purple sweet potato starting to sprout

It’s a great use for any small sweet potatoes you might have. I bring them up from storage into a warm room for a couple of weeks, and they will usually begin to sprout, if they haven’t already. Then I use toothpicks (or pieces of bamboo skewer like the below photo shows) to suspend the potato in a glass jar filled with water. I change the water every couple of days, and the sweet potato will start to send out roots in a matter of days. Sitting the jar in a sunny window will speed up the process. I started mine rooting about a week ago. If the sweet potato is too big to fit in the jar, you can cut it and put the cut end down in the water.

rooting sweet potato in water

Sweet potatoes are generally an easy to grow vegetable, but they do need warm growing conditions to perform well. We have long hot summers here, and sweet potatoes thrive. I usually plant mine out in late May or early June. Most varieties take from 100-120 days to mature. Last year I planted on June 2nd, and dug them on October 9th. This year I am growing three varieties: Beauregard (orange skin and flesh), Bonita (tan skin/white flesh), and Purple (purple skin and flesh).

Carla’s Purple sweet potato plant from 2013

Last year I bought my Beauregard slips from a local source. While the sweet potatoes did fine, they apparently were infected with a fungus (Monilochaetes infuscans) that causes a discoloration of the skin called scurf. Only the Beauregard variety was affected, so I know it didn’t come from the soil. It’s harmless to the sweet potato, though it can cause marketing problems if you are selling them. And though it can supposedly make the potatoes lose water faster in storage, mine are still in fine eating shape. The LSU Ag Center has an informative bulletin about this disease: Scurf of Sweet Potato. The fungus can live in the soil for 1-2 years, so I will be sure my sweet potato planting is not anywhere near the spot they were grown last year. It’s always a good idea to rotate crop families, something I do regardless of any problems I might have.

Beauregard sweet potato with scurf

As a result I will not be using my Beauregard potatoes to make slips. I decided to buy from an online source this year, the Steele Plant Co. While browsing their selections I saw the white fleshed Bonita, and ordered some of those too. For years all I ever grew and ate were the orange fleshed varieties. Now I enjoy the purple ones too, and it will be fun to add a white fleshed variety to the mix.