Yes, I also had trouble getting my winter cuttings to root. They leafed out in the Spring, and I thought for sure they had signs of small root growth. Then they just fizzled out in Summer, and became goners.
When I go to the propogation fair in Salem next year, I'll be sure to ask the experts when is the right time of year in our area to start cuttings for grapes.
What kind of varieties are you having the best success with? Are some kinds easier to start from cuttings?
I think I had similar experience with some of our grapes that started root growth and leaf growth and then fizzled - that happened to a few of those 4 but I am holding on in case they can make it anyway. I think I neglected watering the nursery one or two days too late after it got majorly hot and these smaller than 1 gal yogurt containers dried out faster than the 1 gallon pots.
I couldn't tell you the answer to that.. I am very new to grape propagation and know next to nothing about the cultivars.
Maybe try more cuttings next year for better chance of success and keep it somewhere shady/cool until they get going?
Yes, that makes a lot of sense. I know with apple scions, they recommend refrigerating the cuttings until it is the right time of year.
When I do my grape pruning is usually in January, when it is fully dormant, and freezing temperatures at night. By leaving the scions dormant in a cold place, maybe it will help it to build up more energy for roots in the Spring. Last year I tried planting some outside in pots with sand and rocks, but they just seemed too weak to adapt to the change of season. And the ones I forced to start indoors did not much like the lack of sunlight. I kind of think Late April, or Early May might be the sweet spot for planting cuttings.