Peach graft logging spring 2018


#1

I thought I would start a thread where we can all log our peach grafting as we go, so we can in real time see how different timings are working out. Please include the temperature and sun forecast for the next few days when you log your grafting here, as well as how far along your leaves are on the stocks, and anything else you feel is important to mention.

One thing different I am going to do this year is measure field temperatures with a laser thermometer. I expect the sun is a huge factor in warming up grafts and may make it possible to graft in temps quite a bit cooler.

I have a first report sort-of to start things off… I had about 50 peach seedlings I dug up and rather than throw them out I did a few bench grafts (just standard wedge grafts). I put the stocks in a bucket of dirt and covered with a bag to keep moist, then I put in the basement at around 70F, which is about the ideal callous temp for peaches. Two weeks later I moved them to the greenhouse, first in indirect light with the bag, and then slowly removing bag and moving to direct light. I did 4 grafts and it looks like they may all make it. Here is a picture as of yesterday.

There are two pushing leaves, the other two had only backup buds on the scions (I picked the worst wood for this experiment) and those take much longer to get going but I see signs of movement on them.

I am going to plant them out soon, once it looks like they won’t get zapped.

Overall I think this is a strong positive on how 70F works very well for peaches, I had perfect 70F for two weeks here. I did some peach bench grafts a long time ago and did not keep them at such a warm temp and most of those failed.

We are expecting warmer weather later this week and I may be able to start on outside grafting. I’m not sure the trees will be far enough along though, I don’t see any leaves yet on the peaches. Its a very odd year.


#2

I’ve actually been real successful this year with peach grafts with all showing signs of life 7/7 (fingers crossed). All cleft grafts. Part of the success has to be attributed to the wisdom of the forum regarding grafting peaches during warm period. I grafted two in early february when we had a week with 70-80F weather. The other five i did in mid march where we had a week in the low to mid 70s. Ill update with pics.

The only negative has been a nectarine scion that seems to be infected with peach leaf curl. Will the graft be able to push through and be treated next fall/winter?


#3

Awesome!

Don’t worry about the curl, the later leaves will be curl free. What I do on curl infected scions is pick off by hand all the leaves with curl once there are enough non-infected leaves to keep the plant going. The curl never came back the following year when I didi that.


#4

Thanks.


#5

Too cold to graft outside yet, but I bench grafted 3 peaches onto Krymsk1 rootstock and am keeping them inside. I grafted them on Friday 4/6/18. Only one of these pictured is a peach (Polly in the middle), the other 2 are tart cherries on K5, but I also grafted a PF24C and a McKay peach. Right now, they all look like the ones in this picture. If they show signs of success I’ll try to post.


#6

I’m considering today the real start of my grafting season. I made a dozen grafts, of various types, including 4 peach/nectarines, 2 apricots, and 2 plums. I’ll continue over the next few days (and beyond).

It was about 50 today (but felt colder), with tomorrow forecast at 56 and the next two days about 70. Then it goes back down to 50-55 for another week.

Here’s one graft, before I put rubber electric tape on. I used @alan’s splice technique, as well as his scionwood. Splice does seem easier than clefts, at least when you are dealing with very thick scions.

I also did some cleft grafts and will do a mix of both over the next month+. I’m going to try to make sure that I have some of each variety in the early grafts and the late grafts. I’m not sure exactly what conditions are needed for peach grafts, but from what I’ve seen, success is very dependent on them. So it’s best to not put all the eggs in one basket…


#7

I’m also planning to start later today… high 70 forecast. This window will not give us any data on whether high in the 60’s is good as we will both have some days in the 70’s; I have heard only a couple days of optimal callous temps is all that is needed. You are a bit on the cold side though Bob. For me its a completely usual peach grafting temp window more or less.


#8

Bob how much pressure are you putting on the two pieces to get that nice connection? I rarely do splice graft because I always find my cuts to be curved and need a lot of pressure to touch each other. If you just put the two pieces together you’ll see a hole in between. I might need a better knife. I don’t know if the knife alone will make the cut straight, not curved. It might be my cutting technique too. Any how, I find cleft to do better for me. But yesterday I had to do few splice because I was grafting to small branches and I couldn’t safely split them in the middle. We will see how it goes.

For the record i did few peach graft . Temps following 64, 75, 75, 50’s after that.


#9

I try to put as much pressure as possible on them, with both splice and cleft. You can pull pretty hard with the sturdy rubber electrical tape.

Per Alan’s suggestion, I used my Felco pruners to make the cut. Much quicker than a knife and nice and straight.


#10

I’ll also make some next week to see if the stage of development (how close to flowering, etc) is an important factor. I was just looking at last years grafting dates and take rates and I see that my earliest grafts on 4/10 (3 in 3) were followed by 76, 72, 63, 62, 61. Some of the other early success also had some 70’s,

Some of my (relative) failures in May (3 in 8 on the 8th) were followed by 56,61,59,60,51,67,67. Again- that fits the idea that you need 70’s for callus.

But, fast forward a few weeks and the grafts I made on the 23rd, 26th, and 28th are even worse (3 in 15). But the temps don’t look that bad: 68,58,75,71,68,57,60,71,78,74,72. Plenty of 70’s in there and not too hot yet. My thought is that I missed the initial growth flush.

The other counter example I am seeing is 4 in 5 on May 4th, when it had similar (cold) weather to the grafts on the 8th (which had declining results). 57, 65, 57, 56, 56, 61, 59.

The very preliminary hypothesis I’m drawing is that where you are relative to bloom/growth may matter more than the temperature. At least in my application. Looking at pictures from last year, peaches were in full bloom around 4/21. It would be nice to be able to say something like graft anytime between 1/4" green and 1.5 weeks after full bloom.

I didn’t record the state of the peach trees last April. But the first Japanese plum flowers had just started to open when I made the first peach grafts on 4/10. This year we are a bit behind that- no open JPlum flowers and the peaches are somewhere between green calyx and 1/4" green.

Two different peach trees in bloom last April:


#11

Do you remember if it was sunny on the May 4th period? Sun can add a big temperature boost. Maybe it was sunny on the 4th period but not on the 8th period?? That could explain the difference there. I plan on measuring wood temps on grafts this spring to see how much the sun warms up the graft unions.


#12

Scott,

Do you cover your peach grafts with brown bags after rapping in parafilm? I am talking about grafts on trees that will be exposed to the sun, not the bench grafts that you kept indoors.


#13

From Weather.com:

The 4 days after the 4th:
rain, partly cloudy, cloudy, and partly cloudy

After the 8th:
partly cloudy, mostly cloudy, cloudy, and mostly cloudy

Looks about even- not real sunny for either. I took another look and don’t see any other factors- there is even a lot of overlap in the varieties and host trees. I suppose it could be that the better scions got used first, but this wasn’t near the end, so I wasn’t really scraping the bottom of the barrel.

Good idea- I should do that as well. I bet the black electrical tape increases the temps a bit.


#14

Is anyone leaving nurse buds below the grafts? Just thinking it might mitigate some of the problem of a peach seedling spending all it’s energy on it’s foliage, then lopped off during grafting.


#15

The 4th has two partly cloudy days and the 8th had only one. Partly cloudy days often have quite a bit of sun, for example I am in partly cloudy weather now and its been cloudy AM then sunny PM. So it in fact could have been pretty sunny. I think Weather Underground may log the sunshine intensity data over the day? Well, I know they log it but the question is how far back they keep it…

I did my grafting yesterday evening in 70s weather. The forecast is 81 partly cloudy - 78 mostly sunny - 68 showers - 60 showers likely - 52 mostly sunny. It was cloudy last night so it didn’t drop all that low in temp, that is another factor giving good hours of callous. The low was 62F. So, I was getting pretty good callous temps for much of the night. We might also need to pay attention to the lows in determining good callous hours, and cloudy weather raises the lows. Perfect grafting weather is fully cloudy and high in the mid 70’s.

The weather now is what I fell is perfect peach grafting weather - highs around 70 and some clouds at night to keep the lows not too bad. My lows are 62 59 57 51 (good) 37 38 (bad).


#16

OK it got up to 85F today … and the grafts are far too hot! They are measuring 95-100F with my IR gun. I was too busy to put foil on this morning as planned but I really wished I had done so; I do have foil on now. I did many measurements and they were nearly all in the 95-100F range, thats 10-15F higher than air temp. For a few on the shady side I removed bark down to the cambium to test and the cambium was also 95-100F. So, it appears that sun is a major factor in success and failure of peach callousing. Too much of this 95F stuff and the grafts will all be fried - thats too hot to callous and they are going to age much faster at 95 than at 45. At 45F they slowly age and don’t callous, no big deal for a bit. At 95F they age fast and also don’t callous - bad!

I don’t know exactly how this translates to what the optimal weather is, but it does explain why cooler air temps can give good results, assuming there are enough sunny hours in there. Cooler has the advantage of not drying out as fast, even if the temps currently are not good for callousing – the graft can just idle until sun warms it up. 70F is the ideal callous temp but thats the internal tissue temperature not the air temperature. My bench grafts showed to me how well 70F tissue temperature can work, I got great results on some poor quality stocks.


#17

I’ve done those measurements in the past with the same results. The take away for me is use black if the weekly temps will be in the 50s and use white or reflective foil if the temps will be 60s and up. Also need to consider sun or cloudy skies.


#18

I tested around mid-day and while the air was 73F, the grafts ranged from 85-100F (though it was quite variable and changed a lot, as I moved over the branch). I don’t know how much impact the black tape (under parafilm) has though, as even ungrafted branches reached the mid-90’s.

Tomorrow may be a bit better- only 67 and sunny here (late day showers). I can see why my failure rate was ~100% when I grafted in the mid-70’s and 80’s.

Sounds right to me. I’m going to keep grafting, with next week in the 50’s (and a few 40’s). In particular, a couple days next week with 55F highs and sunny look like it may reach 70F on the grafts. Maybe more.

The weather was so nice today that I would have taken a day off and been out in the yard all day. But, I have a badminton tournament tomorrow and going in to the office leaves me far more rested (at least physically).


#19

shuttlecocks. :sushing_face:


#20

The order I use (inside to outside): parafilm, black rubber tape, white masking tape. Putting on a layer or two of the white masking tape takes more time, but I feel it’s important under the hot California sun; it’s also convenient to write the variety name on the white tape.