What are people’s experience on percentage of successful Grafts? I get about 95% on apples and pears but only 60 to 70% on Plums and I don’t know why. I use parafilm and Arbrex “heal and seal” with the moisture reduced by 50%. I mainly do cleft grafts with at 12 wraps with the parafilm. Have done about 500 plum grafts this season, mainly Victoria and all in the field. Just love to know what I’m doing wrong
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Hi Billy,
Apple and pear are typically easier and more forgiving than stone fruits.
On plums I usually get about 85-95% take. A lot has to do with the callousing temperature. Grafting outdoors here I start rather early just before I think the springtime temps are going to be about 85-90% of optimal for callousing. See below guidance on callousing temps.
If I am grafting a scion and rootstock where the wood is relatively hard to bend or compress, I typically wrap the graft union with a material much stronger than parafilm. To create the pressure you need at the graft union try either a stronger strip of plastic, or a strong rubber band, or even electrical tape. Any one of these can give you significant tensile strength to tighten up the graft union so that you get more cambium contact as the graft heals. I use this on scions that are greater in diameter that 3/8”. On many of the smaller diameters only a stronger plastic tape is necessary to pull the graft union together. In my area, which may be similar to yours, temperatures are difficult to predict, which is why I start before bud break on the rootstock, to give the graft more time to callous before sap rises, so I typically an using grafts that do not require bark slipping: cleft, whip and tongue, chip bud, modified cleft or double tongue side grafts. I use parafilm to completed seal all scion buds, but no sealers. If I need a sealer I use modeling clay but nothing liquid that could interfere with callousing of the union.
Hope this helps
Dennis
Kent, wa
Hope this helps.
Callusing temperatures of Fruit and Nut trees
Posted on May 21, 2013 by qwertyqweryt61
Many people ask me what are optimum callusing temperatures to ensure a good percentage of viable grafts.
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).
Do not forget tissue damage for most temperate fruit will occur at temperatures over 30 deg C. (86 F)
Temperatures either side of the optimum will also work, but the percentage take will be reduced. See graph below for walnuts.
l
Callus graph showing optimal temperature range
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Thank you. That is very helpful 
Very good
Hope it’s helps
Dennis