Don't thin pears and apples king fruitlets

Seldom is it mentioned on here the existent of king fruits. During bloom their are always king flowers. In my area people indiscriminately thin after fruit set and that is a mistake. King fruits should always be left and in most cases the others fall off. There are some fruits where this is not true with stone fruits being the greatest offender. Back to pears and apples if you accidently remove your king fruits the others will still fall off. @39thparallel and I discussed this many years ago and I wanted to share again for those who do not know this.

“Apple trees (Malus domestica Borkh.) develop an abundance of flowers and shed the majority of fruitlets in the first developmental stages. In this study the process of abscission was monitored in cultivar ‘Golden Delicious’ and linked with the position of fruitlets in the cluster, focusing on differences among central or king flower/fruit (K1), flowers/fruit nearest to the king flower (lower on the peduncle L2) and flowers/fruit located at different positions near the base of the peduncle (L3-L6). Individual clusters consisted of 3-7 flowers the most frequent were clusters with 5 flowers. Abscission was biphasic with the first peak 29 days after full bloom (DAFB) and the second peak 48 DAFB. At the end of the abscission process approx. 70% of all fruitlets shredded. Fruitlets at the central position (K1) were frequently unaffected by this process and developed to fruit in 70% of the analyzed clusters. The ratio between subsisting and shedded fruitlets was the opposite for lateral positions in the cluster; approx. 70% of fruitlets abscised in the clusters with 4/5 flowers. No significant differences in the level of abscission have been observed between the lateral positions in the cluster (L2-L6). A tendency to abscission has been detected for L2 position (lateral fruitlet nearest to the king flower) in clusters consisting of 6 flowers. This was further confirmed at harvest. Fruit from the lateral position nearest K1 were smaller and firmer in comparison to K1, L3 and L4. This demonstrates the obvious dominance of the central fruit in comparison to lateral fruit, especially those nearest to the king fruit. This is particularly evident in clusters with many flowers.”
https://www.researchgate.net/publication/282487292_It’s_great_to_be_the_King_Apple_fruit_development_affected_by_the_position_in_the_cluster

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what’s the takeaway? “don’t thin the king out” is actionable but is there timing advice also? thinning too early could mistakenly take out a king, thinning too late could overload the tree and reduce resources for the apples that are left. what’s the correct timing?

does this apply to asian pears?

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Yes my opinion wait until after fruit drop then thin. The tree naturally thins many fruits without our help. Some fruits e.g. reliance peach do not naturally thin which is unfortunate because it’s up to us.

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It seems that my apples don’t thin themselves much. They have a small fruit drop late in June but with our short season if I wait to thin after that the resulting apples are not as large as if I thin out the blossoms, or just after fruit set. Am I imagining things or could this be true.

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The king bloom will be the largest so if you need to thin earlier you can. In a different climate it could be true that thinning early is good. Different types of apples and pears make a difference. Some fruits are given to overbearing.

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I have apple trees which require early manual thinning to prevent overcrowding and excessive fruit load. It makes sense to me that such thinning would also lead to larger fruit. Moreover, I find that leaving fruitlets crowded enough to be touching for long also encourages aphid and other insect damage. Not all of my apples demand this level of early care, as some partially thin themselves, but others definitely do.

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clarkinks, your conclusions do not jibe with my experience.

I remove damaged fruit first, then deformed, then keep the best looking and largest (usually the king), in that order - although also bias towards easiest to reach quickly with the tool.

If I thin early I notice very little subsequent drop.

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@murky

That does jibe i’m saying people indiscriminately thin not that you are doing it wrong. They thin out their king fruitlets jumping the gun and picking off flowers and small fruitlets before freezes are even over. When people remove flowers and fruits, king fruits are the higher quality fruits. No matter if they pick off the king fruits or not the other fruit don’t improve they removed their best quality fruit. Your being selective which is what you should do. I’m also saying given time nature drops many anyway in most cases. I had 50% drop on newer pears. It’s my opinion most people spend more resources on their smallest tree as well. My resources go towards my best trees. Here is an example who decided me or my tree? That’s pai li pear doing exactly what I’m talking about. It’s not done yet either.

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I see. Honestly some years some of the trees get little attention. I’d like to thin when fruits are dime size.

My experience has been that the apple I leave doesn’t drop, irrespective of whether it was the king bloom. But only one is left per cluster.

The other think I take into account is how thick the stem is and the orientation of the cluster.

Your pear looks like it’s doing a good job of thinning itself :slight_smile:

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@murky

Sometimes a picture says a thousand words I should have included one earlier the post would have made more sense. When people see thousands of blooms they get busy I’m only suggesting giving the tree a chance then implement your strategy taking out the small, misformed, damaged and so on fruitlets. Dime size is perfect you gave the tree it’s time. The remaining fruitlets are the best including the king blooms fruitlets. Many commercial fruit growers Don’t have time they may use a chemical to thin for them in the prebloom stage.

I choose the fruitlets to leave using the same criteria as @murky, except I don’t use a tool to thin the others. I just bend their stems down and away from the center of the cluster by hand, and they usually pop loose without much fuss. I find apple thinning surprisingly restful, so long as I’m not having to work from a ladder.

Peach thinning is a different story.

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Here is an example of what someone might do. Let’s say hypothetically they have a large commercial orchard of 10000 trees that need thinned. They see heavy blooms beginning to open they spray captan to intentionally thin the crop. I understand why they would but I’m saying there is a cost to cutting corners that in some situations may be unavoidable. For the home fruit grower the king fruits are your best fruits. https://www.google.com/url?sa=t&source=web&rct=j&url=https://ag.tennessee.edu/EPP/Redbook/Home%20fruit%20spray%20guide%20PB1622.pdf&ved=2ahUKEwjRvZ7VpazwAhWYWc0KHZPGDzQQFjAAegQIBRAC&usg=AOvVaw3rZdBfzsRckEKrtBcnZSLm

Home fruit spray guide PB1622.pdf (839.2 KB)

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I am noticing on the rf variety “Odysso” the ‘king fruit’ isn’t necessrialy the biggest.
But, generally, I agree that’s the fruit best suited for the long haul.

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This internet blog post shows the king blossom.
This is not my photo. A LIFE OF APPLES: King Blossom

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Some of my pears are doing a better job of self thinning than others in my yard. Drippin Honey, Korean Giant, and Jilin were shedding plenty. Shin Li, Shinsui, Hosui, and Chojuro are holding onto a lot. I’ll probably be spending a lot of time plucking fruitlets in a couple weeks.

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I don’t pay much attention to king blossom/fruit. Instead I leave the biggest fruit. And I often thin before there’s much drop. And I’ve never lost much fruit after thinning. I can leave the biggest and they don’t fall off. I know they aren’t all king. The trees here get so much sun that virtually everything hangs on. You could leave small fruits and most would hang on. I won’t be afraid to take off every king on purpose. If that’s all I took off the tree would be massively overset.

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Many of the authorities on thinning say leave the king blossoms get rid of others. Many pears do it for us to some degree. Anyone using a chemical as a thinner? Some go as far as to say king blossoms make better quality fruit more nutritious and bigger Fruit Thinning for High Quality | Western Washington Tree Fruit & Alternative Fruits | Washington State University

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For some reason Hosui blooms for me but doesn’t set fruit. Chojuro on the same tree is much more reliable.

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I wouldn’t enjoy trying to manually thin an orchard filled with the more productive apple varieties…at least not in tree form. Ain’t nobody got time for that! :slight_smile:

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@fruitnut

Your one of the best growers I know of. When you post this I cannot help but to believe your right. Do you feel the king blossoms size and nature favoring it in my observation is not always applicable. It looks to me like nature is doing what it needs to do in this situation and we need to just let it.