Harvest and storage
Sweet potato growth slows when soil temperature falls below 18°C . When the vines turn black after the first frost, harvest your potatoes immediately. Dig them out carefully because the skins are susceptible to bruises and cuts. Leave them outside on the ground to dry for several hours, then brush off the dirt and gently transfer to a box lined with newspaper. Leave them in a warm (27°C), humid place for two weeks.
Proper curing is essential to create a layer of suberin (a waxy substance that keeps moisture in and helps to heal any nicks or cracks in the skin). Then store at room temperature for up to a year. “[The flavour of] a well-grown sweet potato actually improves in storage,” says Wingate. “The starches gradually convert to sugar.”
Yams vs sweet potatoes
So, are sweet potatoes and yams the same thing? No...and yes. True yams (Dioscorea), which are large, starchy tubers, grow only in tropical and subtropical climates. It's thought that African slaves in the southern U.S. began calling sweet potatoes nyami, which was the name for yams in their homeland. To add to the confusion, some American growers of moist, orange-fleshed sweet potatoes have recently begun referring to them as yams to distinguish them from sweet potato cultivars with a whiter, mealier flesh. The latest wrinkle: a number of sweet potato growers are starting to spell the name “sweetpotatoes.”
Grower Greg Wingate of Mapple Farm in New Brunswick, who ships slips throughout Canada and the U.S., notes that on arrival, slips may look a little sad—yellowed or browned—but they'll soon perk up if properly cared for. If you can't plant them immediately, place the slips in a clear jar and cover the rooted area with room-temperature water. You can also plant them temporarily in a seed flat and keep them in a warm place with light until you're ready to go.
How to - Gardening Resources
Learn to grow a sweet potato
Everything you need to know to grow your own tasty, nutritionally packed super tubers