Growing Sweet Potatoes
This post is part of a series of educational articles on gardening, self-sufficiency and food independence. That’s what The Liberty Garden is all about. To find out more about the mission behind The Liberty Garden concept, go here. Or read all the archives.
As far as vegetables go, sweet potatoes are my favorite, and thankfully, they are extremely nutritious. In 1992, the Center for Science in the Public Interest ranked the sweet potato as the number one king of all vegetables in terms of nutritional value.
In addition to being nutritious, sweet potatoes are easy to grow, typically yield well at over one pound per plant, and do not require refrigeration for long-term storage. What a great recipe for food security.
Personally, I have had success growing (and eating) the following varieties: Beauregard, Carolina Ruby, Centennials, and Jewel.
Sometimes people get confused about the difference between sweet potatoes and yams. Botanically sweet potatoes are broad leafed plants in the same family as the morning glory and in the genus Ipomoea. Yams on the other hand, grown primarily in Africa, are a member of the Lily family and in the genus Dioscorea. The confusion came about in the 1950’s when a few marketing folks in Louisiana thought it would be a great idea to call their new orange-fleshed sweet potatoes “yams.”
To successfully grow sweet potatoes you will need a frost-free growing season of 100 days (or more). Most sweet potato varieties need this length of time from the transplant of a sprout (or “slip”) until edible tubers can be harvested.
Assuming that you have an adequate growing season, your next consideration is whether to grow your own slips or to purchase them. If you decide to grow your own, it takes approximately 6 weeks before the slips become big enough to transplant.
To grow slips, select a few small sweet potatoes and soak them for several hours in water. Place the soaked potatoes in a large flower pot ½ full of dirt. After adding the potatoes, cover them completely with 2 inches of dirt. Keep the flower pot indoors in a sunny spot and well watered. Each potato will produce 10 to 15 sprouts which will have roots near the potato. When it is time to transplant the spouts, simply take the potatoes out of the pot and break off the individual spouts.
It may be possible to purchase slips at your local garden center in early summer or you can order them via the internet. One company that I have had excellent success with is Steele Plant Company in Tennessee. Even if you do not purchase slips from Steele, you may want to check out their page describing the characteristics of different sweet potato varieties.
Sweet potatoes grow best in loose, sandy, well drained soil (well drained is an absolute must for success). My strategy is to plant slips in raised beds with a center ridge 10-12 inches higher than the surrounding area. Each slip should be planted at a depth of approximately 2-3 inches (with the leaves sticking above the ground). Within a row, you can plant successive slips every 12 to 18 inches, but keep your rows about three feet apart so that the plants have adequate room to spread out.
After transplanting, you will need to water each slip immediately and do so every few days until the plants have established themselves. Typically you do not need to irrigate the plants after they are established unless you live in an area with limited rainfall.
Weed early and often as this allows the vines to produce large tubers that do not have to compete for nutrients. When the plants get fairly large, they will shade out any new weeds that might try and emerge. About one month after transplanting, I would suggest that you side-dress each plant with a generous amount of compost (a spade full on each side of the plant).
Lastly, with respect to planting, you will absolutely need to protect your sweet potato vines from deer if they tend to be a problem in your area. Speaking from experience, it is extremely frustrating to have a beautiful bunch of sweet potato vines one day and nubs the next morning.
You will need to judge your harvest date primarily based on the suggested growing time for the variety you have chosen. In most cases the number of days will be 90 up to 120 days. When I harvest, I pull up the vines first and pile them out of my way. In some cases a few of the potatoes may come up with the vines, but that is not typical.
I dig my potatoes with a pitch fork, but a shovel or spade should work fine as well. The key is to dig far enough away from the center of the vine (as most of the potatoes will be in a 12-18 inch radius of the center). Dig down about 6 inches and angle your shovel or pitch fork toward the vine center and gently lever up. The potatoes should lift out of the ground. If your soil is really loose, you can also use your hands.
Try not to leave the freshly-dug tubers exposed to the sun for more than one hour.
The most important part of the post-harvest process is called “curing.” Before you eat your trophies, you need to keep them in a hot, humid, dark area for approximately two weeks. For curing, I store my potatoes in 20 gallon tubs (not too deep) and keep them covered with damp towels in the garage.
After harvesting and curing your potatoes, keep them stored in a cool area in your home (and protected from sunlight). I typically am able to keep my September harvest potatoes until March of the following year.
Good luck. And please ask questions if you need more information.