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iron chelate spray defoliating blueberry bushes?

Posted by brandond 6 (hdavis34@hotmail.com) on
Thu, May 17, 12 at 9:34

I have some blueberry bushes suffering from iron chrolosis,distinct yellow leaves with green veins, with some bushes with all yellow leaves. I have placed sulfur around the bushes even though that will take a few monthes to go into effect. I thought in the mean time I will boost the the plants by doing some foliar spraying with iron chelate. I have given around 7 or so doses. I have noticed after this last spray that some of the bushes are defoliating. In fact I think I might lose one or two bushes. In some of the other plants I have noticed some greening up of the leaves and with that has come a boost in growth. However, in a few bushes it looks like they might bite the dust. Has anyone experienced this?


Follow-Up Postings:

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RE: iron chelate spray defoliating blueberry bushes?

I've sprayed some iron chelate and applied some to the soil. Results have been better with soil application. Neither will make fully expanded leaves greener. It helps new growth.

It might be that the defoliation would have occurred even without the chelate. I can't seeing the chelate being toxic but could be wrong.


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RE: iron chelate spray defoliating blueberry bushes?

I would concentrate on getting the pH down faster then the sulphur will do. It very well could be the pH, not the chelate that's killing your berries. It's amazing how fast they will recover once the pH is right. Problem is as you stated, sulphur is slow acting due to requiring microbes to convert it to sulphate. Might want to consider putting in aluminum sulphate to bring the pH down quickly, although it takes about seven times as much to do so, but much faster. Also watering with low pH water might help as well.

The best solution though may be to prepare an acid bed properly and transplant. I fought my blueberries for years trying to bring the pH of soil that was not properly prepared, and the plants never flourished. Then I decided to create a raised bed, used peat and adjusted the pH before transplant. The plants immediately responded with vigor after transplant. I also mulch with pine bark, and the plants are doing great, and loaded with growth and berries since then.


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RE: iron chelate spray defoliating blueberry bushes?

Brandon, instead of spraying cheleated iron, I would instead try to acidify the soil with some aluminum sulfate. The reason you're seeing iron chlorosis is most likely due to the soil pH, which treating with soil sulfur will be helpful in a little bit, but not right now. Be careful to dissolve in water water in well. Check with a good quality pH meter to make sure your pH isn't too low. Then, you can apply chealated iron as a soil soak if you think you need it. I would suspect that you may even have enough elemental iron in your soil, but due to the pH, it is not being absorbed. Sounds like you've burned your leaves on your blueberries, leave off on the foliar spraying, and try to adjust your soil pH for better micro absorption perhaps.

Patty S.


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RE: iron chelate spray defoliating blueberry bushes?

I actually havent noticed any problems with symptoms like this until my last spraying. I think I got the iron chelate a bit on the strong side with my spraying. I havent fertilized in many weeks, and have made no other changes other than iron chealte foliar spray.


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RE: iron chelate spray defoliating blueberry bushes?

You're missing the point. The fact that you are spraying for chlorosis at all says that the pH is wrong, and the chelate is just a bandaid. You need to get the pH down FAST, whether via aluminum sulphate or a new bed. Address the cause, don't just treat the symptom. This is why you keep having to spray with chelate. Iron deficiency in soil is extremely rare. Almost 100% time, iron chlorosis in blueberries is due to pH, nothing more.


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RE: iron chelate spray defoliating blueberry bushes?

It has been awhile since i used Iron chelate, but 7 doses since spring sounds extreme. As I recall a dose or 2 over the whole season was all that was necessary/recomended for cholrosis.


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RE: iron chelate spray defoliating blueberry bushes?

I realize its a ph issue. IM not denying that. I dont not think a high ph is was caused the defolation of the bushes. They were fine with the bushes being 2 foot tall or so on one day. The day after spraying its when the leaves started to have the blackened look and then fell off. Im not disputing the ph, I just believe the iron spray is what caused the problem. I overdid it.


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RE: iron chelate spray defoliating blueberry bushes?

Thats windfall for that advice. I could never find any info on how many doses was considered extreme. I was just trying to boost the bushes in the meantime while the ph gets adjusted over time. I have been irrigating with vinegar is my driplines.


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RE: iron chelate spray defoliating blueberry bushes?

Just a quick thought or 2 on iron chelators. EDTA should be fine for foliar apps. but won't do a thing if applied to calcareous (high lime)/alkaline soils which require EDHA as the chelator to be effective. Sequestrene 138 is the stuff I use for soil apps. in my very calcareous soil and it works well. This Srping I've been foliar applying it to the pear and it has worked well too. One of these days I'll get around to the soil app.. Can't remember if the bag has a label rate roe blueberries but you can look it up on the net. OOps, I see there is no label rate for blues.


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RE: iron chelate spray defoliating blueberry bushes?

It depends on what kind of foliage spray your using but Ive read that 1-2 sprays per season should be enough. 7 sounds way to high.

Whether it was too much foliage spray with too much iron that made your leaves drop or if they were going to drop naturally, you need to find the root cause and fix it. As stated above, high Ph.


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