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Tuesday, June 5, 2012

Keifer Pear Turning Yellow Needs Second Application


Q. My Kieffer pear, which set no fruit at all this year, got extremely chlorotic, from early April to now. I treated it about 9 days ago with Western Organics' Super Iron Chelate, per package instructions. I see noticeable improvement, but does it need a second application? If yes, at what interval? Does this condition have any relation to the lack of pears this year? Normally, this tree yields over a hundred pounds of fruit per season!
Iron chlorosis on pear

A. If it did not set fruit, did you see flowers? If you saw flowers but no fruit than it was a failure in pollination or a late freeze that took out any developing fruit when they were very young. If you saw no flowers then we must make sure that fruiting spurs, or short shoots, are present on the tree.
            Make sure no one prunes off the short shoots or fruiting spurs of the pear. I attached a picture just to make sure we are talking about the same short shoots that bear flowers and fruit. Pear can also get into an alternate bearing cycle. This means that they can set fruit heavy one year and skip the next.
Keiffer pear
            If your tree bore heavy last year then this is a possibility. Next year if you're pear bears heavy again then thin it hard. This means remove fruit from the tree when it is very small so that only one fruit remains per cluster of fruit.
            40 or 50 leaves are needed to support one fruit. After you have thinned the fruit from the tree, look at it again. If the fruit set is still a heavy load, remove even more fruit. By removing fruit in a heavy set year we can sometimes help shift it back to producing every year.

          As far as the yellowing goes, if it is iron, the veins of the yellow leaves should be dark green while the spaces between the veins may be light green or even yellow in severe cases. In very severe cases the leaves will yellow and not have any green veins at all. In extremely severe cases the leaves may turn black and scorch.
          I do not know this product and the quality of the iron chelate. If this chelate is not EDDHA then you run the risk that the iron it may not be very effective. Other chelates drop their iron if the soil pH is too high and then the iron does not make it inside the plant.

            I would strongly suggest that you look at the ingredients and make sure the chelate is in fact EDDHA. If not, and the label permits, you can mix it with water and use it to spray the foliage or the leaves. If fruit is present you do run the risk of discoloring the fruit with the iron.
           You can try adding this chelate with a dilute source of vinegar to try and push the pH lower bus making the iron available. This is a hit and miss approach. You are running out of time so I would put this on the soil as soon as possible. Make sure you apply this chelate in January or February of next year to avoid this problem.

4 comments:

  1. where does one find a bigger bag of EDDHA, like the one pictured. I know Plant world has some 1 pound containers, and that's all I seem to find online also. Do you know of good sources to buy bulk?

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    1. Plant World Nursery did carry the bigger bags. I am not sure if they still do or not. This bag was purchased from Helena Chemical in Las Vegas. They sell chemicals and fertilizers to golf courses, parks, etc.
      They will sell directly to the public but the best price may be if you are a customer or business owner. A 5 lb bag should run around $85 or so. You might also try Grow Well aka Western Organics.

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  2. The product shown is Sprint 138. It is indeed EDDHA. EDDHA is the most expensive of the chelates and works at pH up to @ 12. If your pH is below 10 you can use the less expensive Sprint 330. Sprint 138 can be found here http://domyownlawn.com/sprint-138-chelated-iron.html and the Sprint 330 can be found here http://domyownlawn.com/sprint-330-chelated-iron.html

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  3. Actually 330 (EDTA) starts to drop iron from the chelate at about pH 6.8 according to pH stability diagrams. Iron 138 (EDDHA)holds iron tightly (more stable) through the entire pH range.

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