Thinning Blueberry Blooms/increasing yield

riverman1May 11, 2012

I was talking to my friend and blueberry farmer the other day about the density of blooms on a plant. He told me that this year he is having his pruners take off a large number of the blooms on his farm to increase overall yield. He told me that during his recent trip to the research center in Oregon that the highest yielding plants look quite "spindly" because they are pruned so hard.......these plants produce 10 ton to the acre by the way. Research is showing that pruning hard actually increases yield. He showed me on his plants that anywhere a branch has a large number of fruiting berries that aren't supported by a good number of leaves that they are pruned off. Flowers low on the plant are removed, branches that split into multiple branches with flowers have one or more of the branches removed. Also branches that are comprised of mostly bloom with few leaves are clipped off. I watched him do this to his plants which are each about 6 feet tall, he just started cutting away limbs loaded with was hard to watch! lol I came home and did some of the same to my plants to see if it helps yield this year. Anyway, thought I would share the idea with you guys.



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Thanks for the info.
How far apart should I plant my young bushes?

    Bookmark   May 11, 2012 at 1:02PM
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fruitnut Z7 4500ft SW TX

How can cutting off a large amount of flowers increase yield? I can see it increasing berry quality, but yield? Blueberries aren't like a lot of fruits that drop excess fruits. I've only seen blueberry drop fruit when highly water stressed. So with more fruits even if they are smaller, I'd think yield would increase.

Could be wrong. Anyone have a theory as to how reducing berry number will increase yield?

    Bookmark   May 11, 2012 at 1:23PM
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From what I read, after the cutting here and there, not much left from the bush!! Where the berries are supposed to be grow out/attach to, in the air?

My heart is still bleeding by thining my pears, now I have to thin my blue, OMG, is there an end.

RM, I don't mean to be disrespectful. But I like someone to start a forum to have a good discussion about this thinning method before I believe your friend is not crazy!

    Bookmark   May 11, 2012 at 1:50PM
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Years ago, a hort prof told me something similar. His theory and practice also left me numb when he was visiting my young plot. As he chatted about optimal production (measured in pounds not numbers of individual berries), he was thinning off/removing clutches of tiny berries on any branches he thought too thick. He said the leaves would add their food to the remaining berries which would be larger than if competing for nutrients. All blossom or berry clutches below one foot from soil bed are removed. As a result, with 25 or fewer bushes, production was 350 #s. I could not total the weight of berries eaten by visitors.

This wild spring, with two different heavy freezes, I delayed some of the berry thinning. BTW, thinning is simple with massaging the clutch of young berries and letting them drop to the mulch. Branches that lost most of their leaves were also stripped of all their berries. Now, all the remaining berries are filling out well. The formerly leafless branches are sending out new leaves.

Somewhere on the web is a BB farm in NJ that demos pruning. It is amazing as the bushes are planted 2.5' apart. After pruning, there seems to be more 'bush' on the ground than standing in the row. I plant my bushes 4-6' apart, depending on variety and do prune not quite as much as in OR. Climate here in central KY is much drier than OR, overall.

Olympia, like you, I would love a BB forum! I am especially interested in the varieties that enhance pollination and production of other varieties. If you or anyone else want to add to this discussion, please include me. My absolute favorite pollinator enhancer is a wild bush named Friendship-WI native. It has the smallest berries of any I raise, but also the sweetest. I accidentally noticed how it dramatically increased yield when set between two Elliott bushes. It is simple to divide this variety with an ax or pruning saw. Am about ready to try some propagation of BBs as well.

    Bookmark   May 11, 2012 at 3:09PM
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Blueberrier, Thanks for sharing your experiences of thinning BB. I am so curious now and have so many questions want to ask.
1)Do you fertilize the BB after thinning? If you do, what did you use?
2)Do you cut off the branches like RM's friend did or just strip off the berries?
3)Do you strip off the leaves too?
If the plants have less leaves, does it have less nutrients to support the fruits? If it grows more leaves, does the new leaves grow process take away the plants' nutrients that can supply to the berries?
4) I understand less berries on the tree means bigger berries. How large are the berries after thinned compare to unthinned BB? e.g. If you thin half the berries off the bush, do remaining berries grow twice the size or larger?
5) Is there any specific varieties of BB that works better in this thinning method or this is a "one size fit all" deal?

I have never used Friendship-WI you mentioned. But I would like to try it out if I can get some cuttings. The thing is that it is too early for the bees to do their work. I only saw a big huge bumble bee sorta had hard time to get into the tiny opening of the flower. Poor thing.

    Bookmark   May 11, 2012 at 5:51PM
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Thinning blueberries in a home orchard with less than a 100 plants seems a bit pointless...

I bet that NJ guy is Dimeo Farms...

    Bookmark   May 12, 2012 at 12:47AM
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Olympia, (1) Generally, I fertilize BBs in late March and May. Currently using an OMRI standardbred horse manure compost from the Lex KY area. I also spray with Ca-25 (Calcium supplement-also OMRI rated), and this year gave 1/4 cup of Sea 90 per bush. Every 2-3 years I sprinkle a cup of ag sulfur at the drip line of each bush. Sometimes, I spray a fish+kelp spray. A piece of re-bar or handfull of rusty nails at the plants' bases seems to provide iron.

I no longer pH test any of the soil in this plot. However, if I plant a new to me variety, and it does not adapt in two years, I get rid of it. All the wild/short/ or northern grown wild BBs were fun to grow, taste, etc-but I prefer BB picking from a stool!-or stand-up position!

(2) Since main pruning is late winter, I strip only berries. I also summer prune if I note branches growing in 'rubbing' positions. Have nearly constant wind on my site and do not want wounds for disease.

(3) I do not remove leaves. (4) Thinning of the berries results in optimal berries and more consistent average size for a specific variety. Last year was the most rain of any spring at this location. The Darrow BBs had 7/8" berries which I had never seen before. Each variety has a max size in my experience.
(5) Have not collected data to know which varieties benefit the most from thinning. However, when gathering berries midseason, if I note there are some tiny and not filling out berries, I simply rub then off.

(6) Friendship grows 5-6'+ H for me. Finally assembled inground peat propagation/cutting bed and will try rooting Friendship near some crape myrtle. Sun will be filtered, but no mist system.

Each year, we have hundreds of various kinds of bumblebees and mason bees. They are the primadonnas of pollinators and are not averse to working in wind or misty rains. We farm organically, and have even seen wild honeybees in the BBs, but only during perfect conditions.

Additionally, one of the most interesting aspects of experimenting with different varieties is seeing how each variety responds to ones soil, site, techniques and maintenance.

MoleX, my BB plot is for family use and it requires very little effort to thin IMO. BBs are a significant part of our dessert consumption and are also much asppreciated gift boxes. For me the return on thinning investment is higher than any IRA.

Getting ready to overhead net entire plot as the Gulf Coast is showing color and the mockingbirds are checking daily. Just now, we are getting ready to lay out two lines of drip irrigation for each row of BBs-a first for us. In the past, we would water each bush with five to ten gallons of water if we did not have one inch of rain per week. When this system is in place, we will try twice a week watering if insufficient rain. May invest in a tensiometer to monitor. Can anyone here share which tensiometer they like?

    Bookmark   May 12, 2012 at 1:31PM
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Rusty nails,egg shells,many kinds of rock dust/lime stone will not yield nutrients that plants can use, for years after they are applied to the soil.

    Bookmark   May 12, 2012 at 3:27PM
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Pretty much exactly what blueberrier is saying, less berries on a plant means fewer but larger berries. I have noticed in the past that many of my plants over-produce, that is the amount of berries on them looks out of balance for the size of the plant and amount of leaf structure. Some varieties, in particular Reka which is my favorite seems particularly prone to over-production.



    Bookmark   May 13, 2012 at 7:18PM
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Ok, I have identical 5 year old Jersey Plants side by side, I will thin one and bookmark this thread and report back in a month or so. Now I am curious.

    Bookmark   May 13, 2012 at 8:58PM
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fruitnut Z7 4500ft SW TX

I thin most fruits I grow. It will increase berry size and eating quality. But to say that it will increase yield doesn't stand to reason or any data I've ever seen from other crops.

    Bookmark   May 13, 2012 at 9:29PM
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bamboo_rabbit(9A Inverness FL)

I'm with Fruitnut on this one......thin some of the fruit and the remaining fruit will be larger, that makes sense. But to say that thinning will increase the amount of pounds of fruit per plant? No......

    Bookmark   May 14, 2012 at 7:36AM
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I can't speak for mature plants, but thinning on plants that are immature seems to boost vegetative growth, not increase fruit size from what I've experienced. I'd be curious to know if anyone else has noticed this.

My guess is that in young plants, extra energy from thinning goes to growth whereas in mature plants extra energy goes to fruit. It makes sense when you think of it.

    Bookmark   May 14, 2012 at 10:36AM
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Blueberrier, Thank you very much for the detailed explaination. I appreciate that. I , like you, love eating blue berries. I like eat it fresh picked right from the bushes. I started with a idea of edible landscape planted 6 bushes, now I have a dozen and the # is still growing. I can't resist the temptation of HD blue berry on sale for $3-4. Now I have at least 7 different type of blue berry plants growing in the yard. I guess this is a good thing for corss pollination.
My Chandler is suppose to be largest BB and grow an 3/4 to an inch size berries. If you Darrow can grow to 3/4", this is very impressive size.
The idea of thining it, especailly those on the lower branches, really does not reduce my BB harvest. Most time, I watch my BB grow into good size and turn the color then disappears the next day. I know the 4 legged get ahead of me. By concentrate BB on top of the bushes, might help me better netting the area so I can actually harvest some BB for myself.

I have Duke which has load of BB right now. BB is all over the bushes and is still blooming! I.E I have mixed size of BB and flowers on the same clust. Should I thin the each clust , ie flowers and later grow BB off the clust and leave the early grow BB on ? Or should I just take the entire clust off all together?

BB can be picked 1st season, 2nd season , and 3rd season, etc. If I thin it, does it mean that I only can pick the BB one season?

MoleX, please post the result late this year. I would be very interested to know what is the result of your experiment .

RM, Blueberrier, if you can provide some contact info of that Professor or name of the institution, I would appreciate that, You may e-mail it to my My Page. I am just very curious about this topic. If anyone knows a video of thining using this method, please post the link.

jolj, I have heard that Rusty nails,egg shells does not provide Fe, and Ca to the plant because they do not disolve in water in ionized form . BB soil is acidic, which can disolve more metals, especially oxidized metal like FeO2, than you might think. If you put egg shells in vinegar which is a weak acid, the Ca in the egg shell will disolve into the vinegar in days.

    Bookmark   May 14, 2012 at 2:34PM
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I have no personal experience in how much difference thinning may have on production. However, I will tell you that the farmer that told me about this makes his living growing blueberries and I seriously doubt he would be paying field workers to trim blooms off his plants if he wasn't very confident it would increase yield. Again.....he said the highest producing (tons/acre) were very spindly looking plants when compared to most blueberry plants. To me this really comes as no surprise, if you take off some of the blooms it makes sense that that those remaining would become larger. It's no different really than putting 10 fish in a pond or putting a 1000 fish in that same pond.

There are of course other advantages of reducing the amount of fruit, improvement in plant health, reduction in limb breakage, increased leaf to fruit ratio, and increased fruit quality.


    Bookmark   May 15, 2012 at 12:06AM
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bamboo_rabbit(9A Inverness FL)


I am a proponent of pruning blueberry bushes as I think it does increase both the plants vigor and yield, the following season at least in warm weather areas. What I am having a hard time with is how removing flowers increases pounds per bush that same season. Perhaps what your friend meant is that it increases profit? Larger berries get a premium over small berries and larger berries also decrease picking costs so larger berries do equal more money for the farmer.

Your analogy that removing some fruit makes the rest larger is 100% correct but you will have less fruit so it balances out.

    Bookmark   May 15, 2012 at 9:01AM
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RM, I have no doubt that your friend is serious about this business and he knew what he was doing. He must have been convinced that trim the flower off will increase his tons/acre . It is just that we are here only hearing this practice through you( BTW thanks for shaing the info. It add one more thing that I am interested and want to learn more ) and few others in this forum. Without hearing the rational behind, I can't see the connection between increase tonage by reduce the flowers. That is the reason I would like to talk to the professor to hear how his study /system works and why it works. I am sure he will be thrilled that more people are interested in his work. Maybe he can post something here for rest of us.

    Bookmark   May 15, 2012 at 9:15AM
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It seems a bit counterintuitive I must admit, seems like a large number of small berries would equal about the same yield as fewer large berries. I guess I would just say take the info for what it's worth.


    Bookmark   May 15, 2012 at 7:48PM
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If it improves the flavor,then I like the idea. Brady

    Bookmark   May 15, 2012 at 9:56PM
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