# Leaf splitting



## dodidoki (Jun 15, 2013)

It is a harmless symptom, I only would like to know if there is any cause of this:

leaves split in the middle. I saw this several times on wild collected plants, too.

Eg. my roth:




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## Rick (Jun 15, 2013)

Maybe from bumping into it??


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## goldenrose (Jun 15, 2013)

one would think some type of mechanical damage, if it were cultural I'd expect more than 1 leave to split.


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## SlipperFan (Jun 15, 2013)

I always thought it was from growing too fast.


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## 2Toned (Jun 15, 2013)

I read _somewhere _that variances in humidity contribute to this by causing expansion and contraction in the cells. Could one of our scientists comment on the accuracy of this, please?


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## emydura (Jun 15, 2013)

2Toned said:


> I read _somewhere _that variances in humidity contribute to this by causing expansion and contraction in the cells. Could one of our scientists comment on the accuracy of this, please?



Rick brought this up a few weeks ago in a post of mine which had leaves with a few splits. The view was that changes in humidity was the cause. It happens in quite a few of my multi-florals.


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## Rick (Jun 16, 2013)

I think you could put this to a combination of two factors. Both of which can be illustrated from the Poole and Steeley paper I posted on a couple of other threads.

For one, Calcium is responsible for cell wall and cross link strength. Feeding high N and K essentially produces Ca deficiency and inherently poor structural integrity of the leaf.

Now osmostic and fluid pressure issues. Going back again to Poole and Steeley, feeding high rates of feed definitely makes for a salty/sugary plant. If you drop the solute concentration at the root zone or supply high humidity you will increase fluid supply to the plant and increase internal fluid pressure and increase susceptibility to damage of leaves. 

Ca only goes into leaves as they are growing, and not after maturity. So old leaves cannot be fixed by changing K Ca ratios until they grow from scratch.


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## dodidoki (Jun 16, 2013)

Here are another photos:

the plant is sold as wentworthianum,but I think fake, first pic dated in 29th of december, 2009, tiny new growths, almost died.

Here are two updates:

as you can see plant is ready to bloom, many growths and roots and leaf-splitting phenomen.

I think Dot has right: it is the sign of fast growing, especially when the edge area of leaf growing faster than the central zone. I think is has no importance, anyway.




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2009., December





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And now.





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And splitted leaf.


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## dodidoki (Jun 16, 2013)

I forgot: I donn't think it is caused by change in humidity, it is constantly around 80-85% in my Gh.


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## Rick (Jun 16, 2013)

I think you will see less and less of this as you progress with your fertilizer change.

My Mexipedium may have been the worst of this symptom before low K.


Although it grew like crazy and bloomed well, the leaves were short and very thick (5mm sometime), full of water, and would split down the mid rib fairly regularly.

With low K the leaves are only 2 or so mm thick, over twice as long, and I haven't seen any splitting on the new growth (so far)


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## ALToronto (Jun 17, 2013)

This can happen when you bend a creased leaf, e.g. when you move plants close together. Most of my oncidiums are like this.


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