It sounds like the roots are in the 鈥渟mall box.鈥 (You know the roots are the sweet potatoes and they are at the base of the vines under the soil, right? Just checking.) Can you take the plant with you, with the box and vines intact? If not, you can dig around in the box and see how big the roots are and decide then whether to take it altogether or harvest what you find.
It sounds like the roots are in the 鈥渟mall box.鈥 (You know the roots are the sweet potatoes and they are at the base of the vines under the soil, right? Just checking.) Can you take the plant with you, with the box and vines intact? If not, you can dig around in the box and see how big the roots are and decide then whether to take it altogether or harvest what you find.