Sweet Potatoes are a sweet tasting, tuberous root vegetable that is packed full of nutrition. They contain high levels of Beta-Carotene, Vitamin A and Vitamin C as well as many more. Sweet Potatoes are not potatoes, they actually belong to the Convolvulaceae- or Morning Glory- Family. They are pretty simple to grow yourself and you’d be hard pressed to find a better yield- both in nutrition and produce- for the amount of time and space it takes to grow sweet potatoes.
How to Grow Sweet Potatoes:
As I said, sweet potatoes are not the same as the potatoes of the Nightshade family, so their growing and planting needs are totally different. Sweet Potatoes are grown from slips, which can be purchased from a local seed or farm store. Slips look like long leafy stems with roots. If you don’t want to purchase your slips you can start them at home from a purchased organic sweet potato (Here is a nice tutorial on starting slips). There are a couple of different ways to start slips, but the basic idea is to suspend or place the sweet potato in water until it begins to sprout and root. This will take about 6 weeks, so make sure you give yourself plenty of time for the the slips to grow. Once they are about 6 inches long, preferably with roots, you pinch the slips off of the sweet potato and plant them.
It’s Planting Time!
Site and Soil Preparation:
Sweet potatoes are very easy to grow and don’t have a lot of requirements, but they do prefer a warm, sunny location, so make sure you plant them where they will get full sun. They also do not tolerate cold well, so plant them well after the threat of frost has passed and the soil has warmed. They do need a long growing season, with the normal planting time being in May and Harvest in October, just before first frost. Sweet potatoes do well in most areas, and need little in the way of soil amendments. They do however need a light soil with good drainage for proper tuber formation, so if your soil contains a lot of heavy clay be sure to amend it to make it more of a sandy loam- or grow them in containers.
In terms of fertilizer, sweet potatoes do need a healthy, fertile soil but unlike most plants they don’t require a lot of Nitrogen. Too much nitrogen will actually cause the leafy top growth to grow very well, but with very little development of the tubers you want! So save your chicken manure for the tomato bed!
Planting Your Slips:
Sweet potato slips are usually long stems- at least 10-12 inches long. When we buy them they come in a bunch of 50, and must be kept constantly moist. So if you don’t plant them right away keep them in a bucket of water so they don’t dry out. When you are ready to plant, you want to plant them about 12-18 inches apart in holes at least 6 inches deep. Some people plant them in rows, but I tend to make just one big bed with the plants evenly spaced throughout. I don’t have a need to walk through the bed once the vines take over and I take an early harvest from the edges. When planting the slips, plant them deep- burying them up to the top leaves if possible. Any part of the stem that is underground will grow roots and give the plant a stronger start. Water is very important during the beginning stages of growth so make sure to water well at planting time, and while their roots are getting set.
If you don’t own your own land, have a small yard or don’t have the space to devote to growing sweet potatoes in the ground, they actually do quite well in containers. They do need space to grow the tubers- but any large container will do for a planter. I have seen people use 5-gallon buckets, bushel baskets, and even large growing bags. Simply fill the container with a good, light soil and plant your slip up to the top leaves. I would only do one slip per container, so that they don’t get too crowded. The vines will grow everywhere, but you can add a trellis to the container or just let the vines spill over the edge onto the ground around them.
It’s a good idea to mulch your sweet potato bed, especially in the beginning. The vines will spread , but they can be slow to start, so be sure to keep the bed as weed free as you can until the vines take over. We use black plastic mulch, since it helps to warm the soil and prevent weeds. Growing on plastic mulch will also prevent the vines from rooting. If you choose a different mulch, or none at all, be sure to lift the vines occasionally to pull up any vines that may have rooted so that they will put more energy into the main crop instead of lots of little ones.
I mentioned before that water is very important in the early stages of growing sweet potatoes. They can be very sensitive to drought so if you don’t get rain, they need to be watered at least once a week for the first few weeks. After about a month, the vines should be strong enough to take care of themselves in terms of weeds and water, but if you are in a drought, they will benefit from a weekly deep watering. Once it gets closer to harvest time, the opposite is true- too much water can cause the tubers to rot, so don’t water at all during the last few weeks before harvest and just let Mother Nature call the shots.
The vines are very vigorous, so be prepared for them to go everywhere! I think they are quite pretty, and in the fall they will start to bloom with flowers that are similar to their cousins the Morning Glory. If you are short on space you can grow them up a nearby fence or trellis. Resist the urge to cut the vines if they get outside their assigned plot- the vines are feeding the plant! You can, however, try and turn them so that they continue to grow back towards their garden bed. I consider sweet potatoes to be a “plant it and forget it” type of plant. I plant it in May, water nightly for a couple of days and then just leave them until fall when I harvest. They are a very easy, low-work, plant to grow.
It’s Harvest Time!
Sweet Potatoes can be harvested as soon as they are a suitable size, usually in late summer or early fall, but their flavor and quality will improve with exposure to cooler temperatures. The longer you leave them in the ground the higher your yield and vitamin content will be. I usually start pulling from one or 2 plants in early fall, but save the bulk of the harvest for later. Once the weather has turned cooler and you get close to your first frost date you can begin your harvest. It is best to do it all at once, on a warm sunny day. Since you want them to sit in the sun for a bit after they are dug up, it is also best to dig them when the soil is dry. The majority of the tubers will be directly under the plant, but they can be up to 12 inches away as well. Most people use a spade fork to harvest, but a shovel will do just fine. Start at the outer edge and dig carefully so you don’t damage any of the tubers. Allow them to dry in the sun for at least a couple of hours before bringing them in to cure. The plants are very sensitive to frost. You can leave them in the ground until the first frost, but be prepared to get all of them out of the ground immediately if you do it that way.
How to Cure Your Sweet Potatoes:
Curing is an important step to ensure that your sweet potatoes will last as long as possible, as well as improving the flavor and texture of the tubers. You can cook them straight from the ground- I do all the time- but their natural sweetness increases with curing. Curing will also help to toughen the skin and heal any nicks, cuts or damage received during harvest which will make them less likely to rot during storage. To cure you want to lay them out in a well ventilated room with a temperature of about 85*F and a high humidity. We usually lay them out on newspaper in front of the fireplace/wood stove. Keep them curing at this temperature for about 10-14 days, then move them to storage. Proper storage temperature is also important in order to keep the sweet potatoes in top quality. Optimum storage is dark with a temperature of 55-60*F. If you cure and store your tubers at the optimum temperatures they should last at least a few months. Exposure to colder temperatures tend to cause the centers to harden and higher temperatures make the tubers dry and stringy or them may begin to sprout. We store ours in one of our lower kitchen cabinets- it’s dark and the farthest room from our wood-stove, so it’s usually pretty cool.
Optimum temperatures are hard to recreate in a home environment, but if you can get close to them you should be able to keep your sweet potatoes in a good, eating quality through out the winter. They are still edible as long as they are not soft, wet, showing signs of rot or sprouting. If they are exposed to cold temperatures- such as from being stored in the refrigerator, they will be hard, tough and virtually inedible. If you don’t have a good place to store your sweet potatoes you can always cook them and freeze them, or try and can them using a pressure canner.
Using your Sweet Potatoes:
Sweet potatoes are very versatile. You can bake them and eat them plain or puree them and use them in baked goods. Some of my family’s favorites are oven-baked, seasoned sweet potato fries, sweet potato biscuits, sweet potato muffins and, of course, sweet potato pie. We also enjoy them sauteed with other garden vegetables or just plain with butter.
Have you tried growing your own sweet potatoes? Do you have a favorite recipe that uses them?
© 2013 – 2016, Sarah R Toney. All rights reserved.