Testing Scotts temp theory for grafting peaches

My results for grafting peaches were abysmal for 3 straight years which represented a huge waste of time as I’ve been doing about 100 peach grafts a year in my nursery because I want to offer customers a wider span of harvest for those that only want about a total dozen trees in their orchards. One healthy tree tends to produce more fruit than a family can use if they don’t preserve, anyway.

This year I kept records about weather when I grafted and the following days and temp seems to make some difference, although I’m not sure. The grafts I made when highs were in the mid’60’s took extremely well that were on Flavor May- 6 out of 6 seem to be growing well, so I can’t know if temps are the big deal or if it is the relative growth stage of the tree because Flavor May comes out very fast. Half of the grafts I did were preceding days in the '70’s.

However, my breakthrough was the realization of my last several years of stupidity in trying to keep scion wood from drying out. I was double wrapping bundles with stretch plastic and putting the wood tightly into zip locks with still another plastic garbage with a moist rag in it refrigerating near freezing. Apparently my brilliant method was rotting the peach buds. I started doing this with pears and apples and they weren’t affected but plums may have been adversely affected somewhat and peaches a great deal.

It looks like I’ve gone from 5% to about 80% success with my grafts as a result of realizing I was rotting the buds. Speaking of stupid, the only way I figured it out was from the off smell of some of the wood. However, it didn’t have to smell bad to have killed buds.

This year I just packed the buds loosely in a single ziplock freezer bag and put the bags of different wood in a garbage bag with a moist rag. I store my wood in a cheap beer fridge (or dorm fridge) for its lack of a dehumidifier.


Timely post, Alan.

The first 17 grafts (3 apricots, 14 peaches and nectarines combo) were done on 5/14/21 when temp was 70 F and stayed in the 70’s for 4-5 days.
All 3 apricots took.
12 peaches/nectarines took.
The 2 graft of the same peach variety failed.
Post mortem showed the scionwood turned brown. I believe the failure was due to scionwood’s poor quality (frozen in transit?).

I added 2 new peach grafts on 5/21. This time, temp was in the 80’s. Both took.

Overall, 17 of 19 have worked. That’s the highest take rate I have had.

To me, high temp (70-80 F) is one of the key factors of grafting success (or failure). Other factors are quality of wood and grafting techniques (for maximum cambium contact).

I’ve always wrapped scionwood with stretched parafilm and kept it in ziplock bags in a fridge. This has worked extremely well. The first batch of nectarine scionwood was sent to me in Dec. It spent 5 months in a fridge before I grafted it. All 10 grafts from the Dec scionwood took.


Callusing temperature for peaches based on a study that I don’t have a link to but I recorded their results:
Peach optimum callusing: 64.4 to 78.8F
Tissue damage over 86F

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For peaches it seems everything matters. Quality of wood, quality of stock, quality of weather, quality of graft.

This year I stupidly grafted peaches on some stocks the deer had stripped twice the previous year and I had also moved them over the winter. I had forgotten about this fact until I had already finished the grafting. None of those grafts took whereas most of the other ones worked. Two of the stocks didn’t even re-sprout new shoots, they are dead.



Still, temperature seems to matter more for successful peach grafting than when grafting other common fruit like plums, cherries, pears, apples, etc.


I have a part of my nursery that is fenced to let apple trees get above the browse line before transplanting and I graft a lot of my apple trees there. Trees are planted way close and takes are affected just by digging up trees nearby, it seems- cutting some of their roots. Anything that slows the vigor of trees makes it harder for grafts to plug in.

Another factor is probably humidity. Struggling grafts are more likely to survive in a greenhouse where the humidity is constant, so I’m sure more humid weather is also somewhat helpful. This year I didn’t notice a problem when we had rain the day after I grafted. I’m pretty sure a stretch of cool wet days would tell a different story.

As far as temps, my big take-away is that mid-60’s is OK if that’s when you have time to graft and probably better to do it sooner than wait until beyond Memorial Day up here in NYS. All of my grafts were splice secured with vinyl electric tape, which doesn’t girdle stonefruit at all. No need to cut or unravel later, although I do eventually remove it by unraveling when it doesn’t hurt the bark.

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That has been more or less my typical success rate with nectarines over the past few years… I always graft when temperatures are in the mid sixties-high seventies for a few days.

Glad to hear that :wink:… I have stored scions that long too without detriment to grafting success.


Your scionwood was meticulously packaged. Thank you.

The weird thing is I have almost always been successful with grafting apricots and nectarines. It is peaches that has given me inconsistently results. Nectarines and peaches are practically the same fruit. Not sure why.

We did not have consistent mid 60’s temp this spring. It was cool/cold for a long time and jump to 70 F all of a sudden. I grafted peaches when temp was in mid to high 60’s successfully. I only need a stretch of about 4 days of consistent temp for successful callusing.

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Was the same kind of graft used and was it whip and tongue?

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