These are the four points of balance that make grafts fail: too wet, too dry, too warm, too cool.
Grafting takes three steps, callous on the scion, callous on the host, and then the callous fusing. The balance is different for every life, but for healing to take place, it needs to be warm enough to callous but not warm enough to dry the scion or flood the graft (certain trees), moist enough to sustain the scion but not wet enough to mold or rot.
Grafts fail when callous does not form or the callous is not in solid enough contact with the host long enough to fuse before the outer layer of the callous dries out and dies. Temperature is temperature OF THE GRAFT SITE. Heating or cooling IS effective (ie wrapping in black).
FOR APPLES/PEARS: Callous temperature between 40 and 65ish, callous dries slowly. WILL callous in cold storage.
FOR PEACHES/PLUMS: Callous temperature between 60 and 80, callous dries and rots quickly.
FOR FIGS: Callous?? They will callous at room temperature, which is how people root them. They flood easily, apparently.
Figs can dry easily too, why I have had failures. They tend to dry around the cut, funny, I have had them fail, cut off dry part and the scion was good, green and moist, and put it back on, two that failed took the 2nd time. Strange plants! I was thinking of using the press and seal glad wrap to keep moisture in the graft longer beside parafilm or buddy tape.
According to Bob Purvis, Apricots grafted to Manchurian rootstock are most successful when callusing at 68-73 F, although I have heard others on this discussion list aim for ~10 F warmer than his target. From what I gather, apricots can be very particular about temperatures at graft time.
Fifth cause of graft failure: like a kid at Christmas, you just can’t resist removing the wrap and peeking, and end up jostling the graft site.
I mean, I don’t do that. Of course not. This advice is just for other people who may be tempted. I, for one, am not. I mean…why would you even think to do that? It doesn’t hurry things along any. It’s either going to graft or it’s not. It’s completely ridiculous, silly, nonsensical—
I have had a few fail by rot and a very few broke and a few dried, but:
Parafilm really helps with drying. It also makes a firm hold if you wrap a bunch tightly over the union (i overwrap pretty aggressively) and it has never girdled yet for me letting it sit until sunrot splits it.
That plus grafting when plants are actually ready instead of too early because i am impatient really help
Why grafts fail is poor technique, wrong time of year or poor budwood. I agree with the 4 causes as well but others also! I always cover the whole scion including the buds with parafilm so it won’t dry out for chip, cleft, bark, whip grafts. I wrap the whole graft with vinyl tape. For t buds I always wrap the whole bud as well. So bud drying out is not a problem with me. If you pick unlikely bud wood that is either too old or too new it won’t work either. I always graft when the bark is slipping and the tree is growing unless I absolutely have to. I don’t graft in hot weather of 90F+. Best time for me to graft is in the fall Sept 15-Oct15 or until the first cold front hits here in Houston area.
A guy gave me 100+ graftable citrus root stock in 5 gallon cans last year. He took a cleft grafting class from a friend in February. My friend shows them how to cleft graft but has bare root root under stock that aren’t growing. My friend also doesn’t spend time showing how to pick bud wood, I reviewed his teaching slides. The guy didn’t know how to chose good bud wood and was trying with some that were too old so 99%+ of his grafts failed. He gave up and gave me the rootstocks, took 2 pickup loads to get them all home.
I teach grafting classes in April when the root stocks are growing or in September before the cold front. I spend some time explaining selecting bud wood. BTW my friend has been teaching grafting classes for 20+ years and hasn’t asked me for my input. I did tell him the story of the guy that gave me the root stocks and how he used too old of bud wood. I’ve grafted citrus(99% of the time), paw paw, pecan, persimmon, pear.
I do have my failures. Sometimes good looking bud wood doesn’t work at all 0%. This fall I bought some very hard to get citrus budwood for $250 for 20 buds I didn’t want it in the fall but took it anyway. I tried to store it in the refrigerator but all the buds died. Oh well, better luck next time.
This has happened to me on apple. What happens is that the scion breaks dormancy before it has a chance to knit to the rootstock and uses up all its stored energy before it can start feeding from the rootstock, and then dies. Sometimes they make it, though.
I’ve tried grafting on my apple 5 times and never got 1 to take. I’ve researched, watched dozens of vids and i still can’t get them to take. going to try again this spring.
I think something basic must be going wrong. Apple wood, in my limited experience, wants to graft for you and a 0% success rate would not be my expectation, even for a beginner.
