How to Grow Sweet Potatoes

Whether baked, mashed or made into pies, growing sweet potatoes at home yields delicious sweet potatoes you can store and enjoy for up to a year after harvesting. Sweet potatoes originally hail from Central and South America. In the United States, people often use the terms "yam" and "sweet potato" interchangeably, but the two actually refer to different plants and different tubers (the proper name for the part of the sweet potato that grows underground, and forms the part we eat.) Yams actually hail from Africa. You can grow sweet potatoes in many of the 50 United States, as long as you choose a variety suited to your area.

Sweet potatoes have firm, red to orange flesh. They are related to the morning glory plant and are of the genus Ipomoea. Although only distantly related to the white baking potato you're probably familiar with, the two plants share a similar name. Their planting, care, and storage are quite different, however.

I don't know about where you live, but where I live in southern Virginia, prices for sweet potatoes have gone through the roof, and organic sweet potatoes were ridiculously priced. Yet last year, I grew 79 pounds of sweet potatoes for a $16 investment in sweet potato slips or starter plants. Learning how to grow sweet potatoes is both an investment and an adventure. If you have full sun and decent garden soil, you can grow sweet potatoes.

Unlike many other vegetables, sweet potatoes are grown from root stock called sweet potato slips. You can purchase these in the spring at your local garden center, but it may be easier to order them from a major plant nursery such as Burpee or Park Seed online. They will ship your sweet potato slips around the time they need to be planted. When they arrive, it's important to open the box and remove the plants even if you cannot plant them the same day. I stuck my sweet potato slips in a vase of water and kept them in the kitchen for a few days before planting them; inclement weather kept me from planting the poor sweet potato slips. They didn't seem to be adversely affected by their brief change of job description from vegetable to house plant!

There are many types of sweet potatoes, and it's important to choose one suitable for your part of the country. Sweet potatoes tend to need long spells of very warm or hot weather to mature. The shorter maturity varieties such as Beauregard do well in zones 6 and higher; others that need even more time to mature include Hernandez, Jewel, Georgia Jet and others. Check with your local County Cooperative Extension office to see which ones they recommend.

You should only plant your sweet potato slips after the last danger of frost is past. That time period varies based on your gardening zone. Once the soil is warm, it's time to plant them. Like most vegetables, sweet potatoes do require full sun, or six or more hours per day of direct sunshine.

Sweet potatoes can tolerate an acidic soil, and they don't need a particularly rich soil either. What they do need is room, and plenty of it. The wider the space between the rows, the bigger your sweet potatoes will grow. You'll need to push the soil up into what are called hillls along the rows. Think of a hill in the landscape; your garden bed should have a distinct "hill" running through it. Each sweet potato slip is planted in the hilled up soil. Leave at least 9 to 18 inches between the slips and about 3 to 4 feet between the rows. At first, this is going to look like a lot of space, but you'll thank me later when the plants take off. Soon, the vines will cover the hills!

For the first six weeks or so, water your sweet potatoes if you aren't getting an inch of rain per week from Mother Nature. They can tolerate heat and drought pretty well but if your garden is going through a really dry spell of a week or two without rain, they'll appreciate the supplemental water.

Weeding should be done for the first six weeks or so, until the vines cover the garden bed. After that, the thick vines smother out any interlopers quite nicely.

Keep track of when you planted your sweet potatoes, and the approximate time to maturation. That's the time when they should be ready to harvest. This is the tricky part of the whole process. Growing sweet potatoes is fairly easy - nature takes care of the hard work of providing sunlight and water (for the most part). But harvest is something you'll need to do at the proper time.

I use a hand trowel or spade in my backyard garden. This has some drawbacks. First, if you nick the skin, it will leave a dent, and the dent tends to rot. The best method in a small backyard garden is to use a hand trowel and gently dig into the soil to find the sweet potatoes. Then, using the trowel and your hands (wear sturdy gloves), dig up the sweet potatoes. Discard the greens into the compost pile.

Once you've dug up your sweet potatoes, they need to "cure" so they store properly. In the southern United States, farmers talk about curing houses or small sheds or shacks on farms specifically for the purpose of preserving sweet potatoes, but few people have access to such facilities. Instead, you'll need to provide hot, moist conditions for a week to dry off the sweet potatoes, then store them in dry conditions at around 55 to 60 degrees Fahrenheit.

Here's what I did. After digging up my sweet potatoes, I placed them in single rows in cardboard boxes. Then I left the boxes in my garage with the window cracked open to let the moist, hot summer air enter. After a week of this, I moved the boxes down to my basement, which stays around 60 degrees. That worked well here in southern Virginia. Again, your cooperative extension office can advise you on what to do in YOUR part of the country.

My sweet potatoes stored for over a year, and we are still enjoying them. As long as they are kept cool, they should last for a while. Any that seem questionable should be composted or discarded.

Growing your own sweet potatoes is enormously rewarding, both financially and personally. As I mentioned, I spent $16 on sweet potato "slips", and not counting the cost of building my raised bed garden (which is actually amortized over several years), I grew 79 pounds of sweet potatoes from that $16 investment. I actually weighed all those cardboard boxes on the scale and this is a picture of my sweet potatoes! Yes, you can grow them yourself. Just try a few next spring and see what happens. Happy gardening!