Today I replanted my sweet potato vines. A friend showed me how they did it and I thought I would try it her way.
First you make mounds in the ground - like little graves. Mine are about 1m square - just due to my spacing. You can make them longer.
Then take a vine that has some red on the end and a leaf on the other and wind it up.
Plant it so that the red part and most of the stem is under the ground - I did two to a mound.
Voila - wait 3 - 4 months and you should have a decent crop!