It’s not too late to make sweet potato slips.
Sweet potatoes are now a winter staple in our household, because they are tasty, nutritious, versatile in the kitchen, fairly easy to grow and store well.
Despite their name they are NOT a potato (no more than a day-lily is a “lily” or a primrose a “rose”). Nope, they are not even closely related t potatoes botanically speaking, they are in fact in the morning glory family – as their botanical name indicates: Ipomea batata. Why should I care, do you ask? because it helps understand what they like to grow well and how to store them so they last for you.
Sweet potatoes are tropical perennial vines. In tropical climates, they just grow and grow and grow… and produce lots of tubers, and big ones too, without having to be replanted every year. That’s permaculture! In Virginia – and other temperate climates – they grow until killed by cold. And so every year, they must be planted anew.
You can buy “slips” (very small started vines, often barely rooted), plants (rooted and potted slips) or you can start your own. Really you can, and it’s not too late.
Since sweet potatoes doe not do well until the weather is quite warm, here in Virginia you have till the end of May / early June to plant them, and still have a good harvest, as they will grow well through September and sometimes October (when we have a warm fall). The sooner you plant them once it is warm, the larger the harvest and the heavier each individual tubers. Which some people don’t like. Some people do not want a 5-lb sweet potato! So for smaller tuber, plants your sweets in late May.
It really is easy to make your own slips. All you need a good looking, firm sweet potato (preferably one from last year’s garden but a purchased one if needed as long as it’s a healthy firm sweet), a pot, some soil, and a very sunny window or a cold frame.
Pot the sweet potato with good fertile potting soil, with the stem end sticking out slightly. Check before you plant: a sweet potato that’s been in storage may well start to sprout. Plant the sprouted end up (that’s the stem end). If you can’t tell, plant it flat, covered with 1/2″ inch of soil. If you do not have a pot large enough, use a shoe box or something similar (place in a waterproof pan first). Put it in your sunniest window — on a heat mat if you have one. Give it a saucer (if using a pot). Water liberally (at least once a day), mist often. The warmer and the more humid, the faster sprouts will grow. You could also try to plant it directly in loose sandy fertile ground in a very sunny cold frame, barely covering the top of the potatoes. Again, water well. Obviously, the latter might be more finicky if the temperature drops down below 50F (10C).
The potted sweet should start spouting in a few weeks.
Once the shoots are 3 to 4 inches tall, carefully remove them trying to get a bit of the tuber’s skin. Immediately insert the shoots in a moist light fertile soil. You should be able to get 12 slips or more from a sweet potato. I use tall cell packs to give them room to grow but you can also use 2″ or 4″ individual containers. Don’t plant them all together into another containers as the roots will tangle up.
Put your sprouts back in your sunny window (on your heat mat if you have one) and continue to water liberally (at least once a day) and mist a few times a day if you can. After a couple of weeks, the slips will develop roots. As soon as the roots show through the bottom, you can plant the slips out — ASSUMING the nights are reliable above 60F (15C).
Don’t throw out the original sweet potatoes which sprouted all those slips for you. Leave one or two shoots on it, and plant the whole thing. It deserves it!
And that’s it!
Yes, I know about growing tubers in a glass of water (with the help of toothpicks to hold it half above the water line), but this method of starting them in soil works much better for me. Give it a try!