Oncidium S/H update + leaf spots! (HELP PLEASE!)

[Wynn Dee13]

I have read somewhere (I think my Orchids Magazine) that Oncidiums get these brown tips easily. It said it is from too much fertilizer or not enough humidity for the thin leaves these plants have. I don't think it is a fungal issue. The last picture looks like it is from mechanical damage. It is unsightly but I don't think it will kill the plant. The plant looks healthy otherwise. I also have heard from Ray that pot size in S/H isn't a big deal. Nice new roots!

[Brenda Aarts]

I have to ask-- what's the blue color on the top of your leca?

Bill[/QUOTE]

Bill, I think it's just the leca pellets have chipped, so the grayish blue is the inside of the pellet.

[empiref]

Originally Posted by billc

I've been growing oncidium intergenerics for over 10 years and have had them in s/h for about the last 5 and the leaves always look like they've been thru the worst care. The spots and browning at the ends don't seem to affect the plants. I usually cut the end off at an angle when it gets too ugly.
I have to ask-- what's the blue color on the top of your leca?

Bill

Thanks Bill for your answer,

Can you please point out in which pic you saw the blue?

[RosieC]

The second and third pictures show blue, but I think it's an effect of the flash/lighting on the camera's white balance that's making the grey inside the lecca look blue.

I agree with others that Oncidiums can get brown tips and brown spots very easily. If they are not spreading as such I usually don't worry about them. I can't see anything of concern in your pictures.

[empiref]

Thank you all for your help.

I cut off the parts of the leaves diagonally, and sprayed a generous amount of 1/4 diluted Listerine on the Oncidiums.
will repeat that every two weeks and hope everything will be fine.

[Ray]

The "blue" is actually gray.

The iron ion the clay used in producing LECA turns grey/black under the reducing conditions of the fuel-fired kiln. The outer surface re-oxidizes upon exiting the kiln, turning the orange color we all recognize.

The reason one can "get away with" overpotting a plant in LECA is due to the wicking abilities of the medium.

In a pot of any medium, most of the water loss from evaporation occurs at the top surface, with some also occurring at the medium interface with the pot (even if it's plastic). In poorly-wicking media, there is uneven moisture distribution, resulting in a soppy "core" right in the middle of the root mass, where the bridging water can suffocate the roots. In a medium that does wick well, the moisture is distributed fairly uniformly, avoiding the problem.

[empiref]

I did some research and found this article on the AOS website relating to effect of fertlizer burn on orchid leaves.

Fertilizer Burn

Maybe that's the problem.

[emmastone]

Looks like a couple of things going on to me. First, the tip of the leaf turning brown could be from excessive fertilizer (salts) build-up in/on/around your orchid plant's roots. The issues down the leaf look more like sun burn caused by perhaps water or oil magnifying the intensity of the sun on the leaves. JMHO. I sure others will offer a different opinion.