Thank you @Fusion_power for adding your experience and knowledge to the list. I might just try that inlay side graft with walnut this year. I surely could improve my success rate with that species. Last year I only top grafted walnut and from your description, it sounds like that might be the mistake.
Anyway. The key question in this thread is about optimal temperature for callus formation in different species. I can see some people have interest in discussing the value of botanical names and using celcius. Those who assumed I was not a native English-speaker and not from the US, you are right. And yes ‘E plum’ was short hand for European Plum. I will spell that out in the list to make it clear. One person asked whether I would call a tree in the forest Maple or Acer and the answer is probably neither, we have our own names where I come from - ahorn, ær, løn, navr, depending on species. Botanical names are precise and relatively international. It’s what many colleagues in Europe use to communicate with each other. I can see this forum has an American norm, that I wasn’t aware of. I’m happy to answer any translation issues! Perhaps the meta-talk belongs in another thread?
This would merit it’s own thread and I would be interested to know too. We could include this in the list, I don’t mind. The reason why I want to know the optimal temperature is because that is the point where I will get the best success. Some species I graft in a hot pipe and can adjust the temperature precisely - then it makes sense to use the best temperature, not just any arbitrary temperature that might or might not work.
It’s a mix of personal experiences and sources from books and internet (mostly google scholar searches), as I write in the post. I haven’t saved the source unfortunately, just noted down over time. The reason why I ask in this forum is to get better knowledge. You say there are some definite mistakes. Could you be more precise? Then I could add it to the list (if only I could edit it, which I see now I can’t)
You mention a combination of temperature and growth of rootstock (leaves 1-2cm). I find through extensive personal experience that the latter is completely unnecessary. All you need is temperature and the graft will take.
Yeah, i think so. But meanwhile IMO (speaking as an American) I think that Americans are too quick to assume that everyone else should accomodate to us. I wish more of us empathized with the non-American members. Correspondingly, I also wish that more of us could communicate in something other than American vernacular. ANyway, you shouldn’t be made to feel guilty for trying hard to communicate to us in our own language. That’s way more than most of us would do.
ramv, my presumption for these sorts of recommendation is that may be location specific. Like the folks who say a when persimmon leaves are the size of a mouse’s ear are probably in places that have real spring weather where its over 70F in the daytime once they start growing and stays that way.
I said before I believe there is value in this thread but very difficult for me to understand. So I attempted a conversion of one bullet. I’m not a scientist nor do I use metric enough to do the math in my head. I rounded measurements to the nearest 1/16 inch.
OP text:
Prunus persica 18-27°C. When the leaves are 2-4 cm seems to be the best time
American english conversion:
Peach 64.4-80.6°F. When the leaves are 13/16 to 1 9/16 inches, seems to be the best time.
Did I convert this correctly? If so, I will (as time permits) convert all of the bullets in the OP.
Ignore the leaf length guidance, it is a redundant condition. The fact it is there makes me not trust the data very much. Someone translated the length of mouse ears rather too precisely.
The temp guidance numbers are approximate. You don’t need to convert that precisely. Many of these are most likely taken from originally US sources and converted from F to C and rounded up or down.
In other words try to be approximately right and call it good. We are not doing high precision machining.
Sorry long ago, I once was a machinest and mold makers apprentice. I still am a wood worker, perhaps that shows a little. Be thankful I didnt convert to a thousandth of an inch.
I asked Copilot to convert to F. Then to add common names. Then to round to whole numbers. I only spot checked: Each step took seconds. With forethought it could have been done in one go.
To save our devout friend the individual strain:
Fir (Abies): 68-77°F
Maple (Acer): 70°F
Kiwifruit (Actinidia): 59-70°F
Horse Chestnut (Aesculus): 72°F, max 18 days, medium callousing
Serviceberry (Amelanchier): 68°F, max 18 days, high callousing
Pawpaw (Asimina): 55-75°F. Usually quite light if not done very late. Leaves of 1-3 inches
Birch (Betula): 72°F, max 18 days, medium callus formation
Hornbeam (Carpinus): 72°F, max 16 days, high callus formation
Hickory (Carya): N/A
Chestnut (Castanea): 70-72°F, max 18 days, high callus formation. High callus after 8-9 days at 73-75°F
Citrus Trees (Citrus): 70-84°F
Hawthorn (Crataegus): Late winter to early spring. Highest success rate in March
Cornelian Cherry (Cornus mas): maybe 77°F. Beginning callus after 17 days at 70-77°F
Hazel (Corylus): 14 days at 70°F, 68-70°F, max 14 days, high callus formation
Quince (Cydonia): 55-86°F
Persimmon (Diospyros): 70-81°F. Leaves 0.4-0.8 inches. A little later than others to release the bark
Beech (Fagus): 68°F, max 18 days, medium callus formation
Honey Locust (Gleditsia): 68°F, max 18 days, medium callus formation
Ginkgo (Ginkgo): 72°F, max 18 days, medium callus formation
Walnut (Juglans): 77-81°F, while others use just 64°F, max 18 days but with low callus formation. Beginning callus after 17 days at 70-77°F
Tulip Tree (Liriodendron): 75°F, max 16 days, high callus formation
Apple (Malus): 45-70°F, optimally 55-64°F. There is an early and rather strong growth period for apple, which late grafts may miss
Medlar (Mespilus): Closely related to Serviceberry (64°F)
Mulberry (Morus): 68-77°F, 18 days, high callus formation
Spruce (Picea): 68-77°F
Pine (Pinus): N/A
Peach (Prunus persica): 64-81°F. When the leaves are 1-2 inches seems to be the best time
Apricot (Prunus armeniaca): 64-81°F, optimal at 68°F. Like peach and almost as difficult
Plum (Prunus domestica): and probably others in section Prunus, 55-70°F (61°F), e.g., Japanese plum and European plum 55-70°F
Pear (Pyrus): 45-70°F, optimally 55-64°F, like apple but lighter
Pomegranate (Punica): 64°F
Oak (Quercus): 72°F, max 16 days, medium callus formation
Grape (Vitis): 70-75°F or even 81-90°F. About 6 inches growth before it is typically warm enough to graft wine. Or wait until 12 inches and graft at the base of the new annual growth
Jujube (Ziziphus jujuba): 59-81°F. Should have small knot growth of at least 0.2 inches
You know somebody is going to look at this thread and say they take grafting serious around here. Yet others will look and scratch their head and say what is the dial thing. I can get you a
micrometer measurement if you like but it wont be a digital readout.
