# Suspicious spots on renanthera



## OrchidIsa (Mar 16, 2015)

Hi everyone

Can someone help me with this one? Weird spots appeared on the last two leaves of my renanthera... I put it away from my other orchids but don't know what to do with it


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## gonewild (Mar 16, 2015)

Are the spots reddish purple?


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## OrchidIsa (Mar 16, 2015)

Yes they are. The color on the picture seems accurate (on my screen...) The ones on the upper leaf have a bit more yellow with the reddish coloration.


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## gonewild (Mar 16, 2015)

It could be symptom of phosphorous deficiency.
What nutrients are you supplying?
The symptoms could appear suddenly due to an environmental condition like strong light or cold temperature.

It looks like the plant lost a leaf on the right side at one time? Was there a disease issue in the past?


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## OrchidIsa (Mar 17, 2015)

The leaves at the bottom were already gone when I got the plant a bit more than two years ago so I can't answer your question about disease in the past. 

About the light and temps, the plant initiated in my orchidarium and then, I got it out and put it in my office with my other orchids (same artificial lighting, less humidity). Temps are a bit warmer in my office than in the orchidarium.

I put it out because of bud blasting last year. I feed with MSU in RO water, 3 weeks per month, at around 150 ppm.

Never noticed this kind of spots before.


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## gonewild (Mar 17, 2015)

Are the roots active and healthy?

From what I can see in the picture it does not look like a disease.


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## OrchidIsa (Mar 17, 2015)

Yes the roots are healthy. With the end of blooming, the plant seems to be resting a bit but it has always grow well.


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## gonewild (Mar 17, 2015)

Do you have an idea of what the pH is?
If it's strongly acidic or alkaline phosphorous could be limited.

When you moved it was the light level actually the same or was it increased? Closer to lights? Getting some sunshine?


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## SlipperFan (Mar 17, 2015)

It looks like a lot of light to me.


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## OrchidIsa (Mar 17, 2015)

gonewild said:


> Do you have an idea of what the pH is?
> If it's strongly acidic or alkaline phosphorous could be limited.
> 
> When you moved it was the light level actually the same or was it increased? Closer to lights? Getting some sunshine?



pH of what? Water or substrate (only a few medium bark chunks)? Water pH is between 6 and 6.5. 

In my office, no sunlight and it's a bit farther to lights than in my orchidarium. The leaves were more reddish back then, now greener. But even with that change of color, the spots are new for sure. It's not that I didn't see them before.


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## gonewild (Mar 17, 2015)

OrchidIsa said:


> pH of what? Water or substrate (only a few medium bark chunks)? Water pH is between 6 and 6.5.
> 
> Both, trying to eliminate possible problems. Does not sound like pH should be an issue.
> 
> ...


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## OrchidIsa (Mar 17, 2015)

How strong... I don't have any instrument to measure.  The plant is about 12 inches below the T5HO fluos (one 6400K and on 2700K).

I'm pretty sure the spots weren't there before. I would have probably noticed something different on the leaves surface. Everything was uniform in color... I feel like it has less light than before.


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