I’ve said it before and I’ll say it again. I typically go through my Liberty apple and take off probably 90% of the tiny fruitlets. And then I go back and thin again. Honestly, some years it seems like that tree produces 1000 times the bloom needed.
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I’m with Mark 50% usually is just the first pass. I often take off 80% the first pass. I took 95+% off some of my fruits this yr. You are going to get biennial bearing if they’re only taking off 50% or even 80% in some cases.
Here’s what’s likely going on. I have to take off so much because I took off so much the yr before. Thus high return bloom. But it’s better than biennial bearing.
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Steve- is there a sweet spot in thinning where you can leave just enough to minimize thinning the following year? I hate to admit it, but I’m lazy 
-and getting more so each year.
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I don’t think so. My solution is to have smaller trees. And in some cases to start thinning by pruning off half the bearing wood. I’ve also thinned Asian pears, which are the worst IMO, by cutting off massive numbers of flower clusters before bloom. You have to get the timing right and it works great. Also thin out the fruiting spurs on the Asian pears. They just set way way too much.
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It’s nice to hear you emphasize how many fruit should be thinned.
Like I saud most backyard growers, esp. newbies don’t want to thin many off.
For ne, when I thin 90% off, my Honey Crisp bears the following year. If not, it goes biennial.
I don‘t thinoff plums as aggressively as I do apples. Maybe, around 50-60%. Plums do not go biennial on me but will produce noticeably fewer the following year.
This is my first year to heavily thin Liberty. They had such short stems the thinning was more difficult. Now if I can take them through to ripening time.
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Nail clippers are good for that
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Nail clippers, those little bitty scissors you girls use on your eyebrows (?), long fingernails, whatever … you need several approaches to break up the monotony.
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I mostly thin apples and pears with regular hand pruners. I try to whack several fruit at once. Only leave the biggest. Take everything off at least half the clusters and usually 2/3 to 3/4. With 5 fruit per cluster and leaving one fruit on 1/4 of the clusters that’s 95% off.
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I hope @mamuang won’t mind but I revived this thread to ask a simple question.
You see, this year thinning for me has been insane. For whatever reason, almost every single fruit tree I have is packed and has a massive overabundance of fruit. Its a wonderful position to be in, except for the thinning work. Anyway, this spring I had one 2 peach trees that I forgot to spray copper on during my dormant copper spraying before the end of dormancy. Well, I was so worried about PLC that I actually sprayed those 2 with about 1/2 strength copper at the end of bloom/beginning of petal fall. It seems that the copper had a bad effect on most of the blooms or premature fruit and caused them to drop (at least that seems to be the cause and is the only reason I think of why these 2 trees had so many fewer fruit). In spite of this “damage”, it really sort of worked out perfectly…these trees have just about exactly the right amount of fruit without thinning.
So my question is this: DO you guys think it might be possible to intentionally spray copper (or something that won’t hurt bees) onto trees during bloom or petal drop with the GOAL of it causing most but not all fruit to fall? In other words, thinning by spray? I think I’ve seen people talk about doing this to apples using sevin, and I may have seen a video somewhere of a large peach orchard where they did this…but I’m not sure.
So how about it? Anyone ever “spray thinned” peaches? If so, with what? How did you apply it and when? I really think I could be onto something here??? Or I could be crazy and my lower density peach trees may be that way for some totally unconnected reason Beats me…I’m just trying to find a better way. @Olpea, do you thin your whole orchard by hand?
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Hi Kevin,
We do thin the whole orchard by hand. There have been a lot of chemical thinners tested on peach trees. I’ve not heard of copper being tested as a chemical thinner for peaches, but it doesn’t surprise me that it thinned blooms or fruits. Copper is known to be fairly phytotoxic. You are probably aware copper will cause leaf drop on peaches, if used very heavily at all. Even in lighter doses, copper will spot the leaves.
There are numerous thinners for apples. That is how apples are thinned in commercial orchards.
The problem with chemical thinners for peaches is the reproducibility of results. Too many times the thinner will not take off anything, or take off too much. I’ve heard of some peach growers out west (where full peach crops are very regular) burn off flowers with chemicals, but that’s not nearly as workable as apple thinners, which thin off set fruit.
A chemical thinner which burns off peach flowers would not be advantageous for areas like mine, where late frosts generally thin the fruit anyway.
I would be interested in your results Kevin, if you decide to keep using the copper to thin.
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Well shoot. So it doesn’t sound like I’m the first one to think about this nor that I’m going to become a millionaire with my idea! ha. But I really am certain that the copper did remove a great deal of my peaches off those 2 trees and it worked out great. However, even I am not ready to risk it on all my trees next year - though I will try 2 different trees again nest spring and test this out. But it seems like it would be highly unpredictable. I mean, I wonder why it left some and removed others? Did it cause every single bloom or tiny fruitlet it touched to abort and the ones left just happened to not get hit by spray (I doubt that because I’m fairly heave handed with my spray). If not, what did cause some hang on others to drop, I wonder? And how would I know I’d get the same percentage next year? Also, I bet the timing would need to be near perfect for partial thinning like I got this year by chance. For sure I can see lots of obstacles to overcome, but I think I will do a little more experimenting next year. I guess even the industry hasn’t answered these questions yet and that’s why you say some chemicals have dropped too many and some too few. But it does seem like there might be some way the big boys could figure all this out. THe only other way I’ve seen thinning done is with something that looked like a weed eater except the end had strings placed in a row about 4 inches apart. You probably saw that video too. It didn’t look to good to me though for a few reasons.
THanks for the reminder about copper causing leaf drop and/or spots. But I’ve absolutely found that out the hard way before by spraying copper after leaf out (don’t ask why I did that, it was when I was starting off). I compeleted defoliated a tree a couple times by spraying. However, both of those times the fruit was marble size or bigger and all held on even when leaves all dropped. Leaves came back and it worked out ok. That’s part of what tells me the copper this year IS what caused my partial fruit abort (thinning) .
thanks, mark
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I think in the case of most (if not all) chemical thinners, they either mimic plant hormones, or regulate them. Carbaryl (the old Sevin formula) is an insecticide which mimics auxins (plant hormones which control growth and plant behaviors). There are quite a lot of chemical thinners for apple trees available.
I’ve heard some peach growers using ethephon as a sort of chemical thinner in eastern peach growing regions in the U.S. It’s labeled for sweet cherries to loosen the fruit, so that it shakes off easier with mechanical shakers. As a side effect it also causes a later bloom in stone fruits. The obvious benefit being later bloom = less risk for frost damage. It also makes the fruit buds more winter hardy on stone fruits (another obvious benefit to peaches). On apples, it’s used as an apple thinner (among other uses). It mimics the plant hormone ethylene.
The drawback is that ethephon also promotes canker in stone fruits like sweet cherries and peaches. It also thins some of the crop the next season (it’s applied in the fall in the dormant season). Another drawback is that it produces inconsistent results in peaches. In other words, there is such a fine line between using too much (and causing too much mortality in fruit buds, which is how it thins the next season’s bloom) and using too little which has little to no effect on the tree. Also depending on the wind direction and speed, it can be difficult (if not impossible) to get perfectly even coverage on a tree with an airblast sprayer. You probably wouldn’t realize it, but a cross wind causes one side of the trees to get about 1/2 the coverage as the other side. That’s because the side of the trees downwind from the cross wind get double the coverage. That is, the airblast sprayer blows the spray into the center of the tree, then the wind blows it back out, so the tree on that side gets double the droplet deposition. Additionally when spraying the other side of the tree, the wind blows the spray through pretty much the whole tree so that the other side which already had double the droplet deposition, gets even more coverage from the natural wind and mechanical wind caused by the airblast fan, if all of that makes sense. In regard to the correct dose, I suspect temperatures may also play a role (as they frequently do with apple thinners). So it becomes really difficult to get consistent results with it.
Quite a few years ago there was a fruit specialist from Missouri university doing some trials of ethephon with peaches. I guess that didn’t work out, because I never heard anything further about it.
I think in the case where bloom thinners have been tried with peaches, the mode of action is simply phytotoxicity. The “thinner” kills parts of the flower, thereby causing “thinning”. Free copper ions are somewhat reactive. They react with enzymes in some living cells. Variability with some flowers or fruitlets, vs. others probably depends on just how much copper each bloom or fruitlet received, along with the stage of development.
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Yeah! Let me think where I heard that before…
Oh yeah, that’s, right after had 40 trees in the ground before “finding” room for “just one more” so that now I am up to 95± 
Mike
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In the 3 years since that post, I’ve held to the above statement and haven’t purchased a single apple tree, other than the one I added to an order that my dad wanted to plant in his yard. Of course, I’ve just substituted jujubes, adding another 57 during those 3 years…
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I still haven’t bought any apple trees since 2017, but have grafted 10 of my own, at a fraction of the cost of one new one.
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I’m up to 122 (but only less than 20 in-ground at this juncture).
Around 135 of 145 apple grafts took…maybe 140, as I notice two more “takes” today.
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I did something similar, though I didn’t buy rootstocks. I just yanked up a few suckers (maybe 7-8) under one of my B9 trees, grafted them, and stuck them in a garden bed ($0 cost…). It looks like some of the suckers died (not much root, as I didn’t want to hurt the parent tree), but I’ve got at least a couple where both the sucker and scion lived. No idea what I’ll do with them. Probably offer them to friends or family this winter and if no takers pot them up (can’t stay in the garden indefinitely).
I’ve been doing the same thing with jujubes, with the exception that I’ve been letting some of the suckers establish in pots before grafting. The idea being that I can eventually have them sized up to the point that I don’t need to buy more trees (when I add more rental properties). Since I’m grafting them myself, they can be more interesting varieties as well.
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Hey Bob. Have you been getting more fruit from your Mirsanjeli Late in recent years? If so, when does it typically ripen for you and what are your thoughts on it?
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I don;t think I’ve ever tasted the Mirsanjeli Late. Something snatched the one I posed about and this year there was no fruitset. I think the tree was set back by about half of it dying last year. I think it was a monomilia infection, where the leaves droop in the late spring. In all the previous apricot trees I’ve seen it in, it would gradually spread over the tree and the whole thing would die. I’ve been spraying more fungicide, so maybe I was able to save this one. It seems healthy enough this year, but no fruit.
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