Here in Idaho we know about potatoes, but this sweet potato thing is a whole different ball game. Sweet potatoes are started from ‘slips’, which are the rooted sprouts.
Begin the process now.
Cut a sweet potato length-wise and place the two halves, cut side down, in a shallow container filled with damp sand. Cover the potato until only the top is exposed. Put the container in a clear plastic bag to make a mini green house and place in a warm area. In about 4 weeks you’ll have sprouts a few inches tall. At that time, scoop out each sprout (try a melon baller!) and plant them in potting soil. Put these plants in a cool spot for a couple of weeks so they can work on root development. (If they are allowed to grow too quickly they’ll get a lot of top growth without the desired root system.) After a couple of weeks, bring the plants out into a bright, warm room and let them start to really grow.
It’s work time for you!
Potatoes need deep, loose soil. Double dig the spot where you’re going to grow these sweet potatoes and then cover the area with black plastic to help warm up the soil. Around the end of April, dig your holes and plant your sweet potatoes into the planting holes. Surround the plants with Walls of Water until all danger of frost has passed. These plants must be protected when planted this early. Our last average frost is May 10th.
Which finally brings me to the questions that started this whole thing.
A Nampa gardener asked what caused her sweet potatoes to turn black before she dug them. Well, there are several possibilities. The soil may have gotten cold before they were dug or they may have been over watered. Sweet potatoes, which are tropical plants, won’t tolerate cold soil at all. They also will rot easily in wet soil. If the soil is heavy and the drainage is poor, that could be the problem. It might also be a disease, but I think that’s unlikely.
A Middleton reader complained that his sweet potatoes weren’t sweet. Once again, a couple of possibilities; it might have been the variety because some varieties are definitely sweeter than others. However, all varieties must be cured for maximum sweetness and my guess is that hadn’t happened.
Freshly dug sweet potatoes are not a finished product.
To cure your sweet potatoes, they need a warm (85-90 degrees F), humid spot for about a week. Putting them in a plastic garbage bag next to the furnace should work. Keep the bag open so the moisture can escape. Curing changes the starches to sugar making the potato sweeter. It also heals injuries to the skin so they’ll store longer. Keep them in a cool, well-ventilated area after curing. Sweet potatoes don’t keep for very long so enjoy them frequently. Give them a try in your own garden. They’re delicious and nutritious. Baked sweet potatoes..yum!