How to Sprout Sweet Potatoes

Sweet potatoes are grown from sprouts known as slips that are started indoors on a sunny windowsill or in a greenhouse. While you can use several tubers if you want to, in most cases, you can grow enough slips for even a large garden by starting just a couple of tubers.


About Sweet Potatoes

The sweet potato is a tropical, perennial vine, sometimes called a yam, although that’s a misnomer. True yams are members of a different family. They grow best in USDA Zones 8 to 11 and may winter over in areas where there is no frost. They prefer a light friable soil with good fertility and need regular water in most areas.

Choosing a Tuber to Sprout

Since you may only use one, make sure your tuber has the following qualities:

  • The tuber is plump and firm; avoid tubers that have started to shrivel.
  • The skin is intact; nicks and cuts may carry bacteria.
  • The tuber has no signs of mold or mildew, such as black spots or an odor.
  • The tuber will fit in your container.

Sprouting the Tuber

Find a glass container that is slightly larger in diameter than your tuber. You want some space but no more than an inch. Insert four to six round, pointed end toothpicks into the middle of the tuber at equidistant intervals. Place the tuber, pointed end down, in the jar so the toothpicks are supported by the top rim. Fill the jar with water until the bottom three inches of the tuber are covered.

Monitor the Sprouting Process

In most cases, your tuber will begin to develop roots within three or four days. Sprouts will appear in a week or 10 days. Each sprout will start to develop its own roots. Let the sprouts grow until they are five or six inches high – this usually takes three or four weeks. Detach the sprouts and place in another glass jar; let them grow two more weeks.

Planting Out

Your slips will be ready to plant about six or seven weeks after you started them. If the weather and soil are thoroughly warmed, you can plant straight into the garden. If not, plant into individual pots for another two or three weeks. Transplant when the weather is warm enough, about three to four weeks after the last frost in most areas.

Other Uses for Sprouts

Sweet potatoes won’t develop tubers when grown in the above manner, but they can be used as an indoor plant. The leaves are edible and can be cooked, dressed or sauced as you would kale and spinach. You can also suspend the rooted slips in an aquarium, where they will remove nitrates and waste materials from the water.