You can keep dormant canes in the refrigerator for about a year before they start to degrade. After 2+ weeks in refrigeration, the canes can be rooted. It takes about 6 months from budbreak to harvest. This time is the same in the greenhouse as it is in the vineyard. If the vines are grown in a greenhouse where day-length and temperature are controlled, it is possible to harvest 2 crops a year @ ~6 months apiece. We just take the canes out of the refrigerator when we start a new batch.