Anyone using hot callusing?

See this article if you have not heard of the technique . I ask this question because as everyone is aware callusing can be an issue on a year such as this where temperatures are fluctuating. I found this patent information on it

I was considering it for my apples, but I’ve had such good success with my bench grafts that I don’t think it’s neccesary.

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Interesting. Its yet another example of the importance of a stable graft union temperature on the warm side for many species. It seems hard to get it set up though.


Hot callusing is necessary with grape cuttings, and particularly grafting. Much better success rate.
I use about 85F for a week or so.

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I too use hot callusing to start my grape cuttings. We have an outdoor wood boiler to heat the house and where the water tubes enter the house we added a valve that diverts some of the hot water so it circulates thru tubes running beneath a metal table top. Wonderful bottom heat for callusing grapes or starting seedlings and cuttings.


I do a similar thing with my coffee machine - root ends on the heat and shoot ends away from heat. Its hard to do the graft union only that way, you would have to keep the whole root structure warm.

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For bench grafting callusing, you use a warm moist sandbox. Since the graft has no roots, you can just lay them flat, use heating mat under the flat.

Those are just cuttings, not grafted.

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This quote from the article indicates that hot callusing is not very important on apple grafts:

Nut trees appear to produce optimum callusing at about 27°C (80°F). Apple trees, on the other hand, produce callus at temperatures below 15°C, and hot-callusing does not significantly increase the graft success rate. The hot-callusing device confines heating to the graft union of the nut tree and thereby avoids premature bud sprouting. The problem of premature bud break does not occur with apples and pears that are grafted and callused at lower temperatures.

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I hot callused with a reptile heat lamp!

I bench grafted peaches/nects to American Plum (1 year old bare root) with simple splice grafts. I bundled all 6 of them together and bagged the roots with moist sawdust/paper. I put them in cold storage with the infrared lamp almost directly on the graft. I used an old dimmer switch to adjust the graft temp to 80ºF. I periodically checked the roots over the 3 week period to make sure they were still wet. The buds near the graft (and lamp) did sprout, but it didn’t do any harm.

Unfortunately, I lost picture of the setup. There wasn’t anything remarkable about it anyway. I think I will wire up some simple carbon film resistors for heat source next time. The heat lamp was overkill. I only used it because it was quick.

Here is current pic of Fantasia on Prunus Americana.


Aren’t peaches and nects considered non-compatible on plum wood? I have one Honey Royale growing on methley right now but my other nectarine and peach grafts have failed on plum.

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Some plums, like American Plum and St. Julien, are compatible with peaches. I’m not sure if there are variety exceptions.

A previous thread on the topic:

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Easy way to callus grape cuttings is to get a aquarium heater and put it in a cooler with a couple inches of water, set it at 80 degrees. Take some kind of container and put 4 inches of coarse washed sand in the bottom of it and place it in the cooler. Stick grape cuttings into the sand and heater will heat the bottoms, but leave the cooler open and in a relatively cool area, like a basement or garage. Make sure sand stays moist and you should have good callus in a couple weeks.

When grafting, you can ‘hot callus’ the grafts by putting some black electrical tape around the grafted area, if you are outside. The black tape will absorb the suns heat and warm the graft area…


Hot callusing seems to be gaining popularity this year. Was curious how many forum members are using it?

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I’ve wondered about using Christmas tree lights strung on something to support them across a row of grafts.

If not apples, then maybe not pears, but yes for peaches and plums?

Everything I’ve read here points to chip budding and other forms of grafting late in the season being more successful for stone fruits, generally.

This link has the best info on hot callus that I’m aware of, although not applicable for field grafting.

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I’ve read that too, but most traded scions won’t last that long so I’m planning to try peaches and nectarines in the spring on rootstock and frame working.

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this is where green budwood comes in real handy and all you gotta do is ask the supplier whether member on here or nursery . . . for green budwood of the same years’ current growth. You chip bud this. You should be looking for bud wood to graft at mid-June . As mid-June is the perfect chip-budding time whether you’re in Hawaii or here at my home in IL. That’s about how I understand things . . . so therefore, hit prople up for budwood from people and it should not matter one iota whether the green wood will be coming from zone 10 or zone or zone 8 or 5. I’m not sure about zone 4? I’d like to know, however, thanks @TheDerek .

Keep chip-budding up until Sept. if you’re desperate to get ‘something’ established. I did it this August with a peach. I simply chipped a bunch of buds onto an established tree and onto a potted-seedling. I got a few to stay dormant; several grew an inch or so and then failed; a few grew an inch and set new buds on wood that is pretty green but hardened off.

This green wood is the same hardiness as wood with bark, of course. That’s how nature is. The cells in the rigid green wood have the same hardiness as the more hardened off cells of wood that had more time/season to harden off.

But, yeah, Sept. and whether zone 10 or my zone 5, you’re at the end of chip grafting time, for sure. When you’re grafting late during summer with chip buds, you need to shade the buds - cause they’ll break bud. After mid-July you gotta keep the chip grafts in as much shade as possible. And don’t overwater, either. After a couple weeks, you can water all you want. While the chip bud knits for two weeks, keep the soil on the dryer side.


Thanks for the feedback @Barkslip.

I’m getting all these dormant peach and nectarine scions mailed to me and since they’re harder to take, using a variety of methods to get at least one to work:

  1. Bench grafting rootstock → Should I pot the dormant peach rootstock when I receive it and graft it once the leaves just start to emerge? (and/or between bloom and petal fall on my established peach trees). Everything I’ve read says to do peaches later than apples so keeping the rootstock dormant seems harder.

  2. Bark grafting on my existing trees → Was planning to do it between bloom and petal fall from what I’ve read.

  3. June budding → T- or chip-bud the remaining dormant scion on the rootstock that didn’t take or existing trees.

  4. Summer budding → I’ll take your advice and look for greenwood sticks from members like you suggested if needed.

I’m hoping that that with multiple methods, I’ll get one or two for each variety to take…then I can use that growth for future replication.

Pot them up and try to hold off a full year to graft.

Wait till temps are midst 75 F for 7 to 10 to 14 days in a row with night temps 50+ and ideally 55 F or greater. There’s never a rush so wait.

Graft your bench graft trees outdoors at the correct temps or find a way to replicate those temps indoors or, use the callus pipe. Use the pipe. It’s in the Guides section.