As a followup from May - of the 5 grape starts we did only 1 has survived and is now growing new leaves and buds. The others died off and began to rot.
The vine that broke off in June that we soaked in water, trimmed, then potted has also grown new buds and leaves. These two vines responded about the same time this week, and are now going 'vigorously'.
The reasons the other vines didn't start are mostly due to handling - we left them outside and they got alot of direct sun frequently. These starts did well inside on the window shelf.
The white stuff is whipped cream - the plants are alittle too close to the sink!