Hi Danny
You can graft green onto green now. I would not wait, but take Advantage of the season that is left in your case. 90s are not too high, simply water thoroughly your donor trees the night before so that your scions are more healthy, then as you cut them, immediately trim off the leafs just above each bud. Choose the most viable buds on the bud stick. Use scions with 2-3 buds only. Immediately throw your scions into a bucket of clean fresh ice water to preserve freshness until you graft. As you use each scion, dry excess water with a clean paper towel, wrap with parafilm and then graft it. Cover the whole graft with aluminum foil shiny side out!
Here is a response I sent to another member today:
The primary factors for a successful graft are:
#1: wood compatibility rootstock to scion
#2: Cambium match, if #1 satisfied then this is the #1.
#3: Callousing ambient temps: well above freezing but below tissue damage during the first three weeks when the graft union is usually fully calloused.
#4: Pressure on the graft union: Smaller diameter scions 1/8” to 1/4”and rootstock require much less pressure than those larger simply because you can close the gap between the two with less effort. I use plain old 1” wide plastic strips to wrap the graft union on the smaller diameter scions; whereas, on larger scions with stiffer wood, I follow the initial plastic wrap with something stronger such as electrical tape or a rubber band to close the cambium gap between scion and rootstock. Electrical tape directly onto the bark is to be avoided for all types of wood, too difficult to remove.
Related to this factor is unintentional girdling!
After the graft union heals you need to remove the pressure around the graft union so that its new bark can expand during the growing season. Failure to do this will most often result in a girdled graft union which will ultimately break off due to girdling! I have lost many otherwise good grafts by forgetting to remove the constrictive tapes!
Any one of the above can lead to failure.
I use the following temperature guide for the type of fruit I am grafting.
Best of luck, if you satisfy all of the above factors, your results will be consistently improved!
Dennis
Kent, wa
Callusing temperatures of Fruit and Nut trees:
Nectarines/Peaches – 18-26 deg C. ( 64.4 to 78.8F)
Apricots/Cherries – 20 deg C. ( 68F)
Plums – 16 deg C. ( 60.8 F)
Apples/Pears – 13-18 deg C. ( 55.4 to 64.4F)
Walnuts – 27 deg C. (80.6 F)
Grapes – 21-24 deg C. ( 69.8 to 75.2 F).
Figs - 23.9- 29.4 deg C. ( 75-85 F).
Callus graph showing optimal temperature range
Do not forget tissue damage for most temperate fruit will occur at temperatures over 30 deg C. (86 F)
So when your graft is in direct sunlight and you are over 70F highs, you should use aluminum foil shiny side out to shade the graft from any direct sun. Sun on a dark object such as electrical tape will fry the graft union before callousing can be completed.
Grafting at the time of year when the temperatures range night and day for at least 3 weeks of callousing will help you achieve the best results.
Temperatures either side of the optimum will also work, but the percentage take will be reduced.
