Purple Skin Sweet Potato

I believe this is known as Japanes Sweet Potato is supermarkets here.  I replanted the vine about 4 months ago and the vines were soon going everywhere so i decided i better harvest whatever there is and replant again.

I grow the vine in a planter so the vines have nowhere else to deposit the tubers except inside the planter.  So when the time
for harvesting comes i simply tip the planter over and look for the tuber.  The down side of this method is that the soil soon loses its nutrients and needs to be replaced. 

I used to plant the vines directly in the ground but what happened was i got a lot of small tubers and it was really difficult to dig them out of the ground.  So i thought i rather have one large tuber than 20 to 30 small ones after 3-4 months..

 

The leaves are also edible but if you cut away too many then the vines won't produce big tubers.