Sweet potatoes are misunderstood. They’re confused with yams, lumped in with white potatoes in growing guides, and rarely utilized to their fullest potential.
These babies are energy-rich, nutritionally dense and potential lifesavers in a major downturn. If you’re not growing them, it’s time to put them on your plans for next year (unless you live in the subtropics, then you still have time).
Sweet potatoes (Ipomoea batatas) are a dicot, unlike the monocot yams (Dioscorea spp.), and are related to many of the taxonomically confusing morning glories and the wonderfully productive “water spinach” (Ipomoea aquatica). They’re also NOT in the same family as white potatoes (Solanum tuberosum). (Perhaps I should write the rest of this article in Latin and skip all the messy parentheses?)
Where was I? Oh yeah. Sweet potatoes.
If you live in USDA growing zone 9 or 10, sweet potatoes are very impressive perennials. Further north, frosts prevent them from living up to their complete potential – but even still, they give a lot of bang for their buck.
How to Grow Sweet Potatoes
The first thing needed for growing sweet potatoes is propagative material, i.e., roots or slips. You’ve probably stuck toothpicks in a sweet potato, half-submerged the potato in a glass of water, then watched vines grow out of the top. As a kid, I did this multiple times and always enjoyed watching the ivy-like vines emerge and tumble across the counter. Of course, eventually the root in the water would rot and make an amazing smell, which would then motivate mom to banish the offending tuber from the house… but we did it anyway.
What I didn’t know back then was this: when vines emerge from the top of the sweet potato, you can break them off when they’re a few inches long and new ones will grow. Plant the little vines and you’re well on your way to growing lots more potatoes. This can be done multiple times off one toothpick-impaled root. I started all my potato beds this year from a handful of little leftover roots from the previous year’s harvest. We start slips in the greenhouse and on windowsills in January, and plant at the end of March. Your local dates may vary, but having a few months to start propagating is a big help.
Of course, if it’s spring and you’ve already got a plant or two in the ground and want to start more, you can simply chop off chunks of the vine and plant them here and there. Water them and they’ll root.
Sweet potatoes have a vining habit and will often produce roots where the vines touch the ground, though the majority of the potatoes are located at the base of each plant. Last year we planted about 30 slips and harvested about 120lbs of roots. This was a great yield, especially considering I barely did anything more than plant, wait, and harvest.
One thing to consider when you plant sweet potatoes: they spread like crazy. I planted them in my wife’s rose garden one year and they basically crushed the roses. On the upside, I got a crate of potatoes… on the downside, my wife cried for three weeks over her silly flowers. I explained to her that you can’t really eat roses during TEOTWAWKI, but it didn’t help.
PRO-TIP: The sofa is a really comfortable place to spend the night.
If you want to get a really good yield on your sweet potatoes, get them in the ground as early as possible. This is a double-edged knife, though, since sweet potatoes are not cold-hardy, being a tropical plant. You need a long season to grow them – but if they freeze, they’re dead. So – early as possible means – early as possible AFTER the danger of frost.
Sweet potatoes like lots of compost and will thrive in mulched beds. Don’t overfeed them, however, since that will lead to an abundance of vines with small roots. I spray them occasionally with a weak foliar fertilizer, if I remember, and they do great.
Since I grow sweet potatoes organically, I do have some trouble with bugs chewing the leaves and occasionally boring their way through the roots. The losses are minimal, however. Sweet potatoes are tough. Just don’t keep growing them in the same place (I broke that rule this year… we’ll see what happens) or you may end up with pest issues.
How to Harvest and Cure Sweet Potatoes
When it starts getting cold outside, it’s time to harvest what you have. If you wait too long, frosts can rot your potatoes. When you harvest them, be gentle! You want the skins to stay as intact as possible to keep them from rotting in storage.
I harvest sweet potatoes during a dry day in Autumn, then spread them out on my back porch under cover. They stay there for a week or two to dry and cure. I turn them occasionally to make sure they dry out evenly, then gather the most intact spuds and store them in cardboard boxes or wicker baskets in the dark. The uglier and damaged spuds get eaten first, and the little ones are set aside for the next year’s seed.
My children eat a lot of sweet potatoes during fall and winter. They store for months in our pantry (the sweet potatoes, not the children) and taste better when they’ve sat for a couple of weeks out of the ground. Our favorite way to enjoy them is baked with lots of butter. They’re good for breakfast, lunch and dinner. (Dang it… now I’m hungry and I’ve got to wait another 3-4 months before I can harvest again…)
Note: if you have longer winters, you may want to can sweet potatoes. I know a local prepper who cans vast quantities of them every fall. In my opinion, they pale beside fresh roots… but still, it’s better than starving.
Further Uses for Sweet Potatoes
Beyond the roots themselves, the extensive vines make a great mulch/compost at the end of the year. I throw piles of them into my food forest around the base of needy trees and let them rot down.
Damaged, bug-eaten or tiny roots make good chicken feed. My birds seem to prefer them cooked, but they’ll still peck away at raw ones when they feel like it.
In warm climates, sweet potatoes make an excellent, dense ground cover for food forests. I’ve planted them here and they’ve come back year after year, though I don’t get many roots thanks to the shade.
One final note on sweet potatoes: though the roots are excellent, the greens are a good vegetable in their own right. We eat them raw in salads, sauté them in stir-fries and cook them as greens. In salads they’re a somewhat bland filler, but cooked they have a nice texture. If you did this with white potato greens, you’d start aching and throwing up from solanine poisoning. Try it with true yams and you’ll likely sterilize yourself with diosgenin.
So see – sweet potatoes stand out from the crowd! They won’t cause vomiting or sterility!
Now if I could just cross them with roses, all would be right with the world.