The same.

I find those rules nearly useless. Maybe I have too many branches. If I leave a peach every 8 inches that's way too much fruit. Whereas with apricots, being half the size, I can see 8 inches being OK.

Let me add that to me it's all about canopy density on these rules. If you have a thin canopy, something you can see through, then a peach every 8 inches and an apricot every 4 inches might work. But if your canopy is dense, many branches and leaves, then to me that's too much fruit to achieve high eating quality.

It also depends on whether you've a large family to feed or just want a few great tasting fruit. Too much fruit and a thick canopy will reduce fruit eating quality.

You can make things as easy or as complicated as you like. 8" is probably a good starting point. Am I going to remove a piece of sub-acid fruit that is 5" away from another but is sizing up nicely? I can enjoy that piece of fruit early while in its crunchy sweet state -- so it's a late thinning of sorts. For now, why not go with 8" and tell us how it worked for you?

Late thinning is useless......once the peaches hit the pit hardness stage thinning will have no effect. The thinning has to be done before that stage to have any effect on the remaining fruit. I am beginning to understand peaches are a pain....hours of fruit thinning gah.

I've long been led to believe that late thinning is not at all useless, just that early thinning increases the number of cells per fruit while late thinning increases the size of cells (not going to take the time to test my memory on google this morning)- early thinning is necessary for largest possible fruit, but I don't believe you need finish the job in one early session at all. I continue thinning until about a month before harvest and often begin when trees are in bloom. I get huge peaches.

FN is a very precise and knowledgeably grower, but I think most people could run with Mr. Clint's method and philosophy with fine results. The main problem is that hobby fruit growers tend to thin much too little or not at all. It is hard for me to thin enough, honestly.

If you want to be more precise, my recollection is you need 30-40 leaves per fruit- assuming all are well exposed to light.

I tend to thin to about 1 per 5" first time through then gradually remove a third to half of remaining fruit based on relative size and lack of insect damage.

Distance between fruit obviously shrinks as the fruit grows so if you are late you'd probably want to leave less distance between fruit.

8-10" between fruit is based on what's needed for large peaches- plums and apricots need about half the space if they are ultimately about half the size.

Distance between fruit recommendations are also sometimes partially based on whether the fruit ripens early or late. Can't remember right now who gets thinned more but someone can google and post it if they like. I might do it if I catch up on all the chores I have to do today.

Well, maybe my memory is playing tricks because I can find nothing on-line that contradicts BR's statement about the necessity of thinning within 14 days of pit hardening. Or maybe my original source was incorrect.

I would still suggest that a partial thinning early and cleaning up later may be the best way to go and it is certainly unlikely you will find any research on that one way or the other. The research I saw was all about completing all thinning at a given time.

We've been through this before and Olpea and Scot provided excellent answers.

Here is a link that might be useful: thinning peaches

My experience is it's extremely difficult to over thin early on. I always leave too much. Usually twice too much even when I'm bearing down. If the fruit isn't easily visible I'd leave three times too much.

I side with the opinion that late thinning is pretty useless. Get it done early if you really want it to do some good whether for fruit size, eating quality, or return bloom. All that fruit you throw on the ground after pit hardening could have, to some extent at least, gone to growing bigger or better fruit that you harvest. If there's good research showing otherwise I'll change my mind. But it has to be done so why not early. A few years I've thrown away wheel barrels full of full size fruit when I panicked late on the thinning. Not again.

I knew a good ole boy in Amarillo years ago who was very keen on apricots. Year after year he got froze out. Of course finally one year they set everything. I tried for all I was worth to get him to thin, no way. Well the fruit matured 2-4 weeks late to miserable quality. Then the next spring half his trees were dead or half dead from being so over cropped. My fruit was way better and no tree damage.

This post was edited by fruitnut on Sun, Mar 30, 14 at 11:52

I will be the first to admit I am next to clueless on fruit trees. I leave that to the experts like Fruitnut and Olpea. BUT. I do know what I read and I read a lot and that was late thinning after pit hardening is of no use.

What I want to know is how Olpea thins all those peach trees or how the other commercial folks do it. I have 7 peach trees and thinning just those 7 trees is a boring seemingly never ending nightmare.

When you are used to thinning, the fruit drops down like rain. The first time through I'm not very particular, second time, a couple weeks later. I leave the biggest, perfect fruit.

I'd guess about 15 minutes per tree each time through, so a total of 30 for a mature peach tree with a 15' spread.

It is always easier to thin other peoples trees than my own. The more you obsess about leaving the biggest peaches the more time it will take.

HM,

An hour ago you did not even know the common fact that late thinning of peaches was of no use, till I, a complete self confessed newbie at fruit trees pointed it out. You then had to use google to research it and found I was right after stating I was wrong. So..... I will use that as a basis for how much weight I give your estimation of the time it takes to thin or care for a peach tree.

This post was edited by bamboo_rabbit on Sun, Mar 30, 14 at 13:21

Fruitnut,

Ok lets say you have a 2' long branch and you wanted to thin to 10". There are only 2 peaches on the limb but are 3" apart is that ok? Is the calculation based actually on the peaches proximity to each other or on the branch length?

Am I correct that while the peaches need thinned the Japanese plums do not?

Peaches can be close but not so close that they'll be touching when they reach full size. Three inches is about as close as you'd want.

I agree thinning fruit is about at the bottom of my list of things to do around the orchard. The only good thing about peaches is you can usually see the fruit but not always very well. Pluots can be worse and there is less color contrast vs the leaves.

I thin Jap plums and pluots just as much as peaches.

If anyone gets desperate and are over whelmed by thinning shake the limbs as hard as you can at about pit hardening. That will take off a good deal of fruit, probably the biggest first but better than breaking limbs

"I thin Jap plums and pluots just as much as peaches"

Oh crap...two more trees to thin. At least oranges have the good sense to drop those fruit it knows it can't hold...

BR, you never miss an opportunity do you? I admitted I was working from memory- and I corrected myself. I often try working from memory just so I don't lose it (not sure it's working). Somehow your favorite gurus, Fruitnut and Olpea, respect my knowledge because they have the means and experience to evaluate it. Why not save your critiques for areas of your own expertise, or at least save them for your own posts- I will avoid them. You have no right to once again break forum rules to spew your venom just because you love war so much and I'm your designated enemy.

Fruitnut, you are the first one I've heard of that doesn't take size of fruit into consideration as far as spacing fruit-what is your rationalization? Seems to me you are wasting fruit, but you are the king of brix.

With plums such as Methely, I often rake them off from the lower side of the branch with my hands before I even begin to select the keepers.

By the way, the comment I made about fruit falling like rain has a back up story. My first full time helper had over a decade experience working in a commercial orchard where he had to thin thousands of fruit trees. I was much more careful about thinning until I watched him do it- he keeps his hands moving fast and the fruit really does fall like rain.

It is a difficult compromise trying to keep the largest fruit while also trying to get the job done with some time efficiency, but by going through once real quick and leaving plenty of extra fruit to thin with care later is the most efficient way I've found of doing it.

Harvestman, if I left that impression I miss spoke. Because I do leave the largest fruit. On peaches that usually means the end of the branch but I leave it there as well unless the branch is too wimpy.

No, I misspoke. I meant taking relative size of fruit species into consideration when determining the distance of spacing between fruit. You said you thinned Jap plums and Aps as much as peaches and I thought you meant you thinned them to similar distance between fruit. That's not what you meant?

It wasn't necessarily faulty memory on my part. I was probably (hopefully) remembering what I read years ago in Childer's book, "Modern Fruit Science" where he states (page 222, BR) "To obtain the greatest benefit from thinning, the job should be finished as soon after the June drop as possible, although it has been shown that for many of the medium and late bearing cultivars some benefit from thinning can be obtained as late as eight to ten weeks before picking".

This is a book I often referred to when I started my business. My copy is torn and tattered from use. I wouldn't assume that subsequent research has contradicted this statement unless someone can show it to me.

What I'd like to know is, if you thin to say 4" spacing early and finish the job a couple weeks after pit hardening, whether the benefits wouldn't be about equivalent of getting the entire job done early. I have to think that once the peaches get larger they pull much more energy from the tree.

I've often followed this course, and gotten peaches much larger than commercial growers get around here. Maybe I'll experiment on a couple of branches myself using the two different treatments.

Ok....lets examine this experts statement......

"To obtain the greatest benefit from thinning, the job should be finished as soon after the June drop as possible, although it has been shown that for many of the medium and late bearing cultivars some benefit from thinning can be obtained as late as eight to ten weeks before picking".

He said "SOME BENEFIT" which would mean limited benefit for MEDIUM and LATE bearing cultivars. Clint is in southern California, he does not have Medium or Late bearing varieties lol. So once again you are wrong.

"I continue thinning until about a month before harvest"

Your own book states only limited benefit from thinning at 6-8 weeks before harvest.

"I continue thinning until about a month before harvest"

Your own long dead expert is telling you your wrong.

This post was edited by bamboo_rabbit on Sun, Mar 30, 14 at 17:03

I continue to thin any damaged and touching fruit, and the difference between a month and six weeks is splitting hairs- not to get to the truth, but to get to HM. There are late varieties that can be grown in CA- but that's besides the point, this has become a general discussion about thinning peaches, and now plums as well.

I can point out how your statement is not literally true in detail but this is not a post about our petty differences- I would hope we both would have something more to contribute here.

One thing I did learn while jumping around the internet that hasn't been discussed is that "excessive" thinning can cause split pits and apparently it it better NOT to thin susceptible varieties before pit hardening or to do so very conservatively.

I probably owe BR's challenge to finding this out and it is useful information to me, so thank you, you cute rabbit, you!

A lot of discussion on this post. I have quite a lot of thoughts on the matter and will apologize in advance for the length of this post.

I hope I don't seem to be taking sides on this discussion with my comments. It's not my intention, rather to offer information as I understand it, or to offer my honest opinions when noted.

I have read thinning after pit hardening has little effect on fruit size. I think this comes from observational research (i.e. measuring fruit size from different stages of thinning). However I have a theory about the physiological mechanics of the phenomenon:

Namely, since cell number is set in stage one, thinning afterward won't increase cell number. This part is well known. Cell size can be increased, but this occurs in stage 3 and is mostly water by volume. This is also documented. The theory comes in that I think cell size is much easier to reach the fixed upper limit. In other words, with plenty of water availability, max cell size can be reached with one peach every 5" or one peach every 10", since the tree is basically transporting water from the roots to the peaches, a fairly low energy task with good water availability. Like I said this is simply my theory to explain the reported observational results.

Many times I've also read to thin early maturing cultivars first, but that may be because they are sooner to enter the pit hardening stage, or because they are simply smaller as a general rule and need the most benefit of early thinning.

All that said, I would still thin at stage 2 or 3 if I didn't get it done at stage 1. Not so much to increase size but because carbohydrates (which are converted to sugar) are still going in the peaches at stage 3 from the leaves, so I would think there would still be some benefit to brix if thinning in stage 3, even if not benefificial to size.

For my own trees I thin the cultivars which produce the smallest fruit first. I also thin them the heaviest. Strangely, I also thin the cultivars which produce the largest peaches very heavily. I thin the small peach cultivars heavily to try to get a decent peach size out of them. I thin very large size producing cultivars heavy because the extreme size can add so much weight as to break branches in wind storms. As Hman points out I am careful not to over thin peach cultivars prone to split pits. PF1 is one of those.

Bamboo,

I can totally emphasize with your frustration with the amount of time it takes. We are certainly not alone. I've read the labor cost in commercial orchards can run as high as $1500 per acre for thinning.

I have 350 peach trees now, but I haven't had to thin my newer planting site yet. This would be the first year to thin that site where most of my trees are. So far I've only had to thin the peach trees in my backyard (only 35 peach trees).

In the past I've left some fruit on small shorter shoots. When I start thinning the newer planting I plan to prune all shoots under 9" off. This should save quite a bit on thinning. I also may start using a toilet brush to get rid of some flowers during bloom. If worse comes to worse, I'll use a wiffle ball bat to knock fruit off. Ultimately, I'll have to hire help to get it done. I'm thinking about calling one of the schools which has an FFA chapter and hiring about 10 high schoolers to help me thin. To that end I have already developed a sheet to give each student, so they have basic set of rules to follow during thinning.

I will retype that sheet in the next post for anyone interested.

Harvestman:

My English was probably subpar. I leave more fruit on small fruited things like apricot and plum than on peach. The thing I really thin hard is my earliest nectarine. Probably 1/2 or a 1/3 the fruit I leave on a late season nectarine. For that thing it's all about a small taste of what's to come and I need 18 brix for that.

Here is a sheet I typed up last year which I plan to give to new help before they start thinning. I may also do a youtube video so my new help can "see" how to thin peaches before they start in the orchard. The sheet has type on the front and back. I think I'll type the front on one post and the back side on a separate post, to break it up.

Front side says:

WHY THIN PEACHES?

Thinning is a process of purposely removing fruit from branches/shoots. It is very important than it not only be done, but done early in the season.

Why thin? Peach trees generally set 70-90% more fruit than they can grow to harvest. Peach trees harvest sunlight to produce fruit. By way of photosynthesis, peach trees use sunlight to convert water and CO2 into carbohydrates and sugars for the fruit. It takes approximately 35 leaves (close to a fruit) to harvest enough sunlight to produce a good fruit. If there are too many fruit, the leaves can't capture enough sunlight to "feed" the fruit with enough carbohydrates and sugars. The result is smaller fruit that is less sweet. Un-thinned peach trees many times produce fruit hardly bigger than a golf ball.

Another reason we thin is that because there are so very many fruit on the un-thinned peach tree, the weight of all the peaches tends to break branches later on.

Lastly, an un-thinned peach load puts more stress on the tree. The tree is putting all the energy it can into feeding an enormous amount of peaches, even to the tree's own detriment.

For these reasons, we remove 70-90% of the peaches early in the season.

Thank you Olpea, great contributions on a subject on which you are very keen. I know you are intent on growing totally kick-ass peaches. I did provide a link to comments you made last year.

I should mention that I've seen terrible consequences this year from trees not adequately thinned last at a couple of sites. For the first time I'm seeing serious canker on trees that also bore crops much too heavy for the trees- or carried the crops too long, anyway. I have no clue why the consequences were more severe this year than ever before- rain was consistent and not excessive last season. There are no unusual factors that come to mind.

This is the second side of the peach thinning sheet. I plan to emphasize the rules are in order of importance. In other words, if a new person can only keep a few rules in their mind at first while thinning, the first 5 rules are much more important than the last 5. I may at some point change some of the rules if I can find a way to make it more understandable.

These are just my attempt to introduce my help to rules I want them to follow when thinning my trees. It's not intended to be dogmatic for folks on this forum. I titled it the ten commandments to make it more memorable for my help, and perhaps take it more seriously.

Ten Commandments for Peach Thinning
(In order of priority)

1. Remove all fruit in the crotch angles of the shoots.

2. Remove all doubles (Siamese twins) and triplets.

3. Leave one fruit per 12" of branch space (i.e. a shoot that is 12" long leave 1 fruit. For a shoot 24" long, leave 2 fruit.) Fruit at the top of the canopy can be thinned less. For fruit at the very top of the canopy, it should be thinned at 1 fruit per 10" of branch space.

4. Round up to the nearest fruit when determining how many fruit to leave on a shoot to the nearest increment of 12. In other words, if a shoot is longer than 12", but shorter than 24", round up to 24" when determining the amount of fruit to leave. As an example, for a 15" shoot, round it up to 24", so as to leave 2 fruit on the 15" shoot. If the shoot is 18" long, round up and leave 2 fruit on the shoot. If the shoot is 26" long, round up and assume the shoot is 36" long, so as to leave 3 fruit on the shoot. For fruit at the very top of the canopy, round up shoot length in increments of 10" for the purposes of determining how many fruit to leave on the shoot.

5. Generally remove all fruit on shoots less than 6" long. (The word "shoot" refers to one-year old growth, not brand new green growth. Brand new green growth won't haven any peaches on it.) The exception to this is that if a branch has lots of shoots less than 6" long on the branch, then leave a fruit on one shoot per 12" of branch space. In other words, if a branch has nothing but short shoots, don't remove all the fruit on the short shoots, since the branch can grow some fruit. Instead leave fruit on one shoot per 12" of branch space.

6. When thinning, try to select the bigger fruits as keepers except when the fruit will be too close to each other (Fruit less than 6" apart is generally too close. Fruit greater than 6" apart is OK.) It's very important to leave the bigger fruits when thinning because the tree will naturally abort many of the smaller fruit later on.

7.No shoot, no matter how long, should ever carry more than 4 fruit. Most shoots will carry from 1 to 3 fruit.

8.Fruitlets hide in the foliage. As you're thinning a shoot, move your fingers downt he shoot to make sure no fruitlets are hiding on the back side.

9. Once you've thinned a portion of the tree, if you enter the interior of the tree to more more thinning, take care not to knock extra fruit off the branches you've already thinned (This is why it's best to thin the middle of the tree first, so you don't have to enter the middle after you've thinned the outside, which will potentially knock fruit off branches you've already thinned.)

10. After the tree is thinned, walk around the tree slowly two times, carefully examining branches to make sure all the shoots were thinned.

Thanks for the compliment Hman. I hope we have to thin this year. I'm seeing some fruit buds swell, but it's still too early for me to determine the extent of the damage from this winter. Here's to hoping everyone has lots of thinning to do - a good problem to have.

This post was edited by olpea on Sun, Mar 30, 14 at 18:48