I have heard 10-14 days for apples to callous and peaches are probably similar. I would hit more like 70 than 80, you don't want to over-activate things.

Recently I have only done field grafts of peaches and cots and there the challenge is finding the period of good temps in the spring since they callous too slowly when its in the 50's. This year I grafted in a couple day warm spell which was perfect but then its been on the cold side. Last year I grafted right before we had these freakish 90 early spring temps and most of the peach grafts failed. My ideal field temp for peach/cot is high 75 low 55 for a week, in those temps I have always had great results.

Scott

Thanks Scott that's helpful. I am pretty sure the material I read on bench grafting apple didn't have them holding at room/cellar temp for more than a week before returning to cold storage. Perhaps the important thing is getting the process started?
It just seems wrong to hold bareroot stock at those temps for that long (10-14 days).... I suppose I could try to keep everything cool and dormant until the weather warms. Do my grafting and immediately plant stuff out...but I am a bit reluctant to try to hold the apricot scion that long...we just lost the snow last week.
Unfortunately most of the benchgrafting info I can find is aimed at large scale nursery/orchard production and nearly all references apple.

If there is not enough callus the grafts won't take, so I would not return after a day or two. Maybe five days would be OK. I would plan on grafting a couple weeks before you can plant directly out, there is no reason to let them sit waiting otherwise. The scions will keep til June or later if you make sure now and then that there is no mold on them and they are not too wet or too dry.

Scott