Grafting workshop

For a number of years I have put on a grafting workshop in early May. We are in zone 5. At this time buds will be swelling but not yet broken. Why this choice of time? Because the afternoon is spent in my orchard top-working trees, and I have found that this is most successful around the time of bud swell. (Any wise comments?)

What I would like advice upon, however, is how best to arrange the morning session, which is devoted largely to basic whip-and-tongue grafting of bare-root rootstocks. What I have done in the past is to keep the rootstocks dormant up to the day of the workshop, graft them in the workshop, and send the participants home with instructions to plant their new babies in their permanent locations as soon as possible. Results have been variable, ranging from 100% take and growth to complete failure of both grafts. (They get to take home two trees). Difficult to separate grafting technique from after-care.

My questions are 1) Do you think I would be better heeling in my rootstocks in a nursery bed a few weeks ahead of the workshop and allowing them to break dormancy? (ie. graft onto actively growing rootstocks)
2) Should I be advising those participants with space to plant the newly grafted trees in a nursery bed for a year (or two?) before moving them to their permanent location? (I appreciate that this is "standard practice", but it is not clear to me just why. It seems to me that disrupting the new root system by digging it up a year later cannot be beneficial either to the tree, nor to its local biome.)

What do those of you running spring grafting workshops do?

Broomholm Orchard
Zone 5b in Nova Scotia

Hi David, We have grafted about 200 trees over several years, and we alway plant in pots, placed in a protected nursery area outside for the first year. This is because we've never gotten 100% success on the grafts taking (my husband has about 85% success rate), and sometimes the rootstocks die (maybe 1%?) and we did not want to go through the work of planting in the orchard more than once. We keep the rootstocks outside, at whatever our temperature is before grafting within a few days of receipt. (so still dormant when we graft) We are very careful when planting the 1 year old trees the following spring to not disturb the roots. I think the pots we use are 2 or 3 gallon? Just big enough for the roots to fill most of the pot in one growing season, but not get tied up and congested. This has worked well for us and folks that have come over for grafting lessons go home with either pots or instructions to pot them up at home. Each of our pots gets a topping of hardwood chips as mulch for the summer hot weather. Pots are easy to come by for free from landscaping companies around here, and the first year of our orchard, this method gave us more time to get the orchard fencing and soil prepared. Of course, after care is pretty critical, enough water and monitoring for bugs/disease. We have our final (yeah, right!) crop of grafted trees that are ready to plant this spring that also got the holistic sprays last year. It's pretty hard to know if the participants gave proper care or if the grafts just failed. We got a pretty good idea of which grafts were failing when doing 50-100 at a time, all getting the same care and close monitoring the first growing season in pots. Hopefully someone else with more experience can weigh in on this.

VistaRidge orchard, Quilcene, WA zone 8a est. 2012
235 Cider and heritage apple trees, 72 varieties,