Let's talk for a minute about pruning, thinning, and math


#1

So I was on a call the other day and heard of a California commercial grower who is shooting to size 900 nectarine per tree. My jaw dropped as I didn’t think it possible to size that many fruit per tree… So then I started to do the math and think about both commercial and home growers and their pruning habits. I’ve been tempted myself to try to produce a pretty (structurely speaking) tree, without actually thinking about my fruit goal.

Let’s do some math. If this grower is trying to size 900 nectarines per tree, and we’ll say a 6 inch spacing per nectarine, that comes out to 450 linear feet of fruiting wood left on the tree. At 5 inches, that’s 375 linear feet.

In another instance, I talked to a former grower and he generally had no more than 75 lbs of fruit per tree (let’s say about 200 fruit). I never saw his trees, but I wondered if he was taking off a lot more fruiting wood without thinking of the consequences.?.

Then there is this PSU article that talks about the same approach from a ‘per acre’ target…

Blockquote
The distance between fruit on a shoot or the number of fruit per tree is not very important, but the number of fruit per acre is critical for fruit size. Therefore, if trees are pruned lightly to retain many fruiting shoots, fruit should probably be thinned to at least 8 inches between fruit. Also consider the genetic component of the cultivar for fruit size. In general, early-season cultivars produce smaller fruit than late-season cultivars. Therefore, early-season cultivars should have lower crop loads and this can partially be achieved by retaining fewer fruiting shoots per acre. The optimum numbers of fruit per acre depend on the cultivar and availability of irrigation. For small-size cultivars a provisional number of fruit per acre is about 45,000, which would require 11,250 shoots if the fruit are thinned to 4 fruit per shoot. For medium-size cultivars a reasonable target crop load is 70,000 fruits on 17,500 shoots per acre and for large-fruited cultivars 100,000 fruit on 25,000 shoots per acre is suggested. To calculate the desired number of shoots per tree, simply divide the desired number of shoots by the number of trees per acre. For example, for large-fruited cultivars with a tree density of 150 trees per acre, retain 167 shoots per tree and retain 4 fruit per shoot to produce 100,200 fruit per acre.

Generally, that article doesn’t make any sense to me in that I would think the distance and number of fruit per tree matter a lot…

Obviously, there is also a lot to be said for variety of tree (genetic ability of the fruit, growing tendency of the tree), but I was curious, is this something y’all have thought about when you go into your orchard to prune or thin your trees? Have you thought about the consequences of removing too much fruiting wood?

This year we’re leaving more wood on than I would normally do, My plan is to go back post harvest and make some heavier thinning cuts at that time and do some more corrective pruning.


#2

The presumption about per-acre mattering appears to be that trees are spaced and pruned to gather maximum harvest of light, regardless of number of fruiting shoots, and it is the harvested light that determines the amount of quality fruit that can be produced per acre in commercial production where all other factors for max production and fruit size are realized.

Most of us on this forum don’t give a damn, because we are trying to produce the best tasting fruit and on good years have much more of the stuff than we can consume. We often grow poorly producing varieties for superior flavor and try to manage all species of fruit we grow to achieve max brix attainable for our region.

Even the small commercial growers I know don’t obsess on bins or pounds per acre- their primary focus is on growing fruit that people want to buy more than what’s in the “super markets” because the flavor is better or the varieties are different. Marketing efficiently is far more important than producing efficiently for small growers. They are selling a special experience- not bargain fruit.

Personally, with stone fruit, I wait until I’m pretty sure of the survival of flower buds, like when the trees are in bloom, and prune to lessen the need to thin. Therefore, I sometimes cut back fruiting shoots and always thin their number with this in mind. I even make peach trees more compact than they need to be,reducing my crop load intentionally by reducing the tree. I also remove shoots that will be at all shaded as much as practical.

I never count how many fruit I get from a mature tree as they are always either loaded with all I want them to bear or more (it is always hard to thin enough on good years) or I have crop failure. Fortunately, it is usually the former two. Some day I hope to acquire the skill to always thin adequately.


#3

And I thought it was just me! In 2016 The nectaplum was my worst fruit, I got a lot of them though (about 80). It was rather bland and tasteless. In 2017 the tree thinned the most had the very best fruit (about 30), that would be the nectaplum. The difference from my worst fruit to my best is a numbers game. Thin like a beast! I’m so glad i didn’t pull the tree as i was about to. The severe thinning in 2017 was not my idea. For whatever reason the tree decided to only flower a little. Maybe buds were damaged somehow? The end result was random fruits spaced super far on the tree. I only thinned a few close ones.
This year looks to have a large amount of flower buds. Not sure what happened last year? None of my other trees did this.I will probably thin to 40 to 50 fruit.


#4

With my Liberty I have a simple formula: Thin to one blossom per cluster, then take off about 90% of what remains! Well, not really quite like that. But I’m always scared by the amount of thinning I do and still impressed by the amount of fruit I get. But that’s Liberty, and they’re not all like that.


#5

The flavor of pears & quality is generally determined I believe by nutrient levels available. My trees get plenty of nutrients from this loam / clay soil once it’s amended with composted manure & woodchips. When I prune I’m careful to remove only what I actually need to remove and not what makes a tree look pretty. In some cases I will see a limb I want to remove but if it’s covered with fruit buds I use self restraint and wait. There are times when the only fruit on a new tree comes from an injured branch , a branch growing downward etc. which are the very branches people remove. A girdled branch, a branch growing horizontal etc. are the branches that spur up first. As @alan has said many times about branch bending it speeds up fruiting but keep in mind trees eventually do that on their own. @alan is right about getting trees to fruit faster which can be critical at times with European pears to get them to fruit faster than within 15 years. Bending branches also keeps trees shorter and more manageable. Once a tree starts to fruit it quits growing as much because the energy goes to making fruit.


#6

How you can be confident of the positive affects of your amended soil being the result of nutrients other than creating porosity (providing oxygen) and/or more available water- clay holds a lot of unavailable water that humus gives away? Of course O2 and H20 are both technically nutrients. If a wide range and ample access to nutrients was that important for flavor, I don’t think my trees in containers would produce as good flavored fruit as my long mulched orchard trees- sometimes the fruit is better- probably aided by some water restriction.


#7

@alan,
It’s more an observation than anything scientific. I don’t always get everything amended but the trees I ammend produce better quality tasty fruit. Amendments like I use help to retain water which in this area does make more nutrients available even if there was no other benefits. This video explains my general perspective on amendments regarding my clay/Loam soil https://m.youtube.com/watch?v=HmEyymGXOfI . This explains absorption https://m.youtube.com/watch?v=Az1h5qMfFQM. This is another video explaining trees https://m.youtube.com/watch?v=f5yRMqaDHN4. I know we have discussed it before but my new trees do not have the microbes present for a tree to be healthy https://m.youtube.com/watch?v=-dhdUoK7s2s. Woodchips and fungi help the new trees succeed https://m.youtube.com/watch?v=-dhdUoK7s2s. My ground was used for crops and not growing trees for more than a hundred years. The concept I use is simple woodchips, manure, clay soil, water, mycorrhizal fungi, sunlight + a fruit tree = fruit. My soil lacked the fungi other soils have due to heavy row cropping which I’m correcting https://m.youtube.com/watch?v=gSY-4AtqQG0. Back to the pruning for a minute if nutrients are added when none are needed it causes excess growth. More tree = more fruit so I do have a tendency to grow large trees and I really like full sized trees. On part of my property deer make it impossible to not grow large trees. I also feel taller trees pull up deeper nutrients which yield better fruit but that is just speculation. My tall trees also get water from deeper down which makes them more drought tolerant. Pruning can definately be good but to much can be just as bad as not caring for a tree at all.


#8

Not sure about Nectarines but a fruit thinning gage is sometimes used on apples.

Its an interesting device, but It would take a while to get good with it. I expect it would be more useful in a large commercial orchard of perfectly uniform trees where the goal is to produce the largest revenue per acre and not just the largest number of pounds per acre. Revenue is a combination of yield, size and quality.

The research indicated that using the gage to determine the optimum number of fruit and thinning to that number produced better results than just thinning based on a rule of thumb spacing.

Alan makes some good points. Our approach is slightly different. We have learned to obsess about the number of pounds of fruit we SELL per acre not the number of pounds we grow. In our case production efficiency is more important than marketing efficiency because we spend a lot more time growing the fruit than selling it


#9

I agree I centainly value what everyone has said here especially @alan . Anytime commercial growers or expert home orchardist discuss perspectives, differences in location lead to differences in opinion. The concepts of growing fruit are fundamentally the same as is pruning but the weather, soil, insect and animal pressure etc. will change how we approach things.


#10

I could see as a home growers wanting to increase your harvest if you used your fruit for cooking. Cooking it down really concentrates the taste, so I don’t know if you could really taste the difference between high-brix fruit and medium brix fruit. (Maybe the same for cider as well? Though I didn’t want to assume, as I’ve never made it before.)


#11

@VSOP what I was thinking of is kieffer pears which are a very heavy producer versus warren which is a very light producer. For cooking you want kieffer but for fresh eating you want warren. If you grew all kieffer you would likely make more money on pear sales. If you grew all warren you could easily starve to death but they would taste good! Some trees are very shy producers. Once I switched from Rutgers, cherry tomato’s & Roma one year and raised Cherokee purple. I normally got 60+ gallons of tomatoes and dropped to 2 gallons that year. I loved the flavor but could not tolerate the production. My love for green gage has kept a tree in my orchard that is over 20 years old now having only picked a few dozen green gage from that huge tree.


#12

On peaches, I almost never remove too much wood while pruning, or too much fruit while thinning. It’s happened a few times but not very often. When mistakes are made, it’s more often the other way around, which is a much worse mistake. That is, leaving too much wood, or too much fruit at thinning.

The comments about small direct marketers are spot on. You have to sell the fruit you grow. Big fruits which taste good SELL.

From my perspective, there is no way I’d leave that much fruit per acre, or per tree. I’ve told people who help me thin that I would rather have 100 peaches I can sell (per tree) rather than 500 peaches I can’t.

Following the article’s math, 100K of peaches per acre divided by 150 trees per acre = over 650 fruit per tree. That would be an absolute disaster here. Not only would I not be able to sell anything, the number of broken scaffolds would be astounding.

As another example, I’ve repeatedly seen new backyard growers on forums leave too much fruit and they are very disappointed in the peaches. Nobody wants golf ball sized sugarless peaches, which is what you get when you leave those kinds of numbers on the trees.

It takes 112 three inch peaches to make a bushel, which equates to a per peach weight of .45 lbs. We shoot for a 1/2 lb. peach in my orchard on mature trees for most mid and late season varieties (early varieties are obviously smaller). To get that, you can’t allow more than about 300 fruitlets per full sized tree. Even then, that’s really pushing it, but if you truly thin to 300 fruit per tree at thinning, quite a few more will drop and the tree will likely reach the desired goal of 1/2 pound fruit. About 200 fruit per full sized tree at harvest seems to be about perfect for me.

The problem is that if you think you’ve thinned to 300 fruitlets per tree, you probably haven’t. It’s so easy to miss small fruitlets hiding in the foliage. Most backyard growers come back repeatedly and do lots of follow up thinning. We try not to have to do too much follow up thinning (it’s not very labor efficient when doing lots of trees) but even we do a little of it.


#13

That is some very useful information.

We never seem to thin the peaches enough but the size is good until we hit our last variety . We average about 12 peaches in a 1/2 peck bag or around 96 per bushel.

Most varieties except Contender are blooming now so with 26 degrees expected tonight the freeze may take care of the thinning this year.


#14

Blueberry,

I should probably clarify that 200 peaches/tree is a pretty low yield by commercial standards. If the peaches average 1/2 lb., that’s only 2 bu. per tree.

For myself, I really don’t follow commercial guidelines as far as yield goes. Otherwise I would be irrigating trees and pushing yield. Our focus is on quality. It gives me a sense of satisfaction to sell big flavorful peaches, and it brings customers back.

As you know we sell peaches for $2 lb. At 2 bu. per tree, that’s $200 revenue per tree. It’s not a huge, amount to work with, but I try to keep costs down to a minimum, and always looking for ways to reduce recurring costs.


#15

Olpea

Thank you for the clarification.

$200 per tree X 120 trees/acre= $24K/acre which looks good to me!