Sweet potato vines react poorly to cold temperatures, and you must prepare them for winter if you want to replant in the spring. To preserve your plant throughout the coldest of temperatures, you have some options, depending on the location of your sweet potato vine. As annuals, expect your vines grown outdoors to die, but by saving the tubers, you can effectively winterize the sweet potato vine's genetic material for replanting in the spring.
Bring a container in which a sweet potato vine grows inside following the first frost. Set in a dark spot, misting it once a week to maintain soil moisture throughout the winter. Move the pot outside after the last frost into a sunny location.
After the first frost of the year, dig up the tubers out of the ground and cut off their stems.
Rinse off the tubers and wrap each with lightly dampened newspaper, storing several in a black plastic garbage bag. Alternatively, fill a plastic garbage bag with peat and bury the tubers in it without wrapping them in newspaper.
Set the garbage bag in a dark spot that maintains temperatures of 40 to 50 degrees Fahrenheit. Spray the exterior of the newspaper or the peat with the mister once a week to keep the storage medium moist.
Re-pot or replant your stored sweet potato tubers after the last frost.
Fill a jar about 3/4 of the way with water.
Stab a ring of toothpicks about 1/4 of the way from one end of the potato.
Place the toothpick side of the potato into the jar. Adjust it so that it is resting evenly on all of the toothpicks.
Place the potato in a warm place, preferably between 70 and 80 degrees F. Choose a location that receives sunlight, such as a sunny kitchen window.
Use disposable wooden chopsticks to temporarily stake the slips as they grow. When they are 6 to 8 inches in length, transplant them to dirt.
Pick a sweet potato that will easily slide into a wide-mouth jar or vase.
Cut the sweet potato in half across the middle.
Place a toothpick approximately 1 inch above the cut portion of the potato in three or four places to create a stable holder.
Fill a wide-mouth jar or vase with water.
Set the potato on the top of the vase or jar, allowing the toothpicks to hold the top of the sweet potato above the water level. The lower inch of the sweet potato should be submerged in the water in the vase.
Keep the jar or vase full of water. You will see the potato begin to sprout vines within seven to 14 days. Allow the vines to grow until they reach 12 inches or longer.
Grasp the sweet potato vine at the base where it joins the tuber. Twist gently to remove the vine from the tuber.
Place the vine in a separate jar or vase of water and allow it to root. This may take seven to 10 days. Alternatively, you can plant the vines directly into a prepared garden space.
Choose a large, firm jicama root for sprouting. It should be free of mold, bruises and discoloration. It's papery, tan skin should be smooth and have no gouges or deep tears.
Place the jicama root inside a paper bag. Set the bag in a warm, dark place. The temperature must be above 65 degrees Fahrenheit for the root to sprout.
Check on the jicama root after a week or two. You should see small sprouts, similar to potato sprouts, forming on one side of the root.
Choose a place to plant your jicama. The area should get full sun all day long, and the soil should be loose, but dark and rich. Pound a small trellis into the area.
Dig a hole about 6 inches deep and wide. Place the sprouted jicama root into the hole and cover it with soil.
Water the root with about a quart of water each week. Water it every three days during dry periods. The jicama should sprout and vine in about 3 weeks. Twine the vine through the trellis.
Preheat the oven to 400 degrees F.
Peel the sweet potatoes and cut into 1-inch wide strips using a sharp knife. Place the strips in a shallow bowl or dish.
Add the olive oil, sea salt and ground black pepper to the dish with the sweet potatoes. Toss the sweet potato strips to coat thoroughly in the oil and spices.
Transfer the coated sweet potato fries to a large cookie sheet or baking pan. Sprinkle with the nutmeg and thyme, and place the pan in the oven.
Bake the sweet potato fries for 30 to 35 minutes, or until fork-tender. Remove from the oven, allow to cool for 10 to 15 minutes, and serve immediately.