Problem with browning leaves on Miltoniopsis and my other Oncidium Alliance chids
 

I seem to have a problem that my oncidium alliance chids have leaves which are browning then dropping off. It's a slow thing, they slowly turn yellow then brown then fall off over a period of a couple of weeks. :(

The worst affected is the Miltoniopsis (which I have had a couple of months) but it's happening on others as well (which I have had for a couple of weeks).

Any thought on what it could be... I've had some thoughts but no idea if any of them are along the right lines or not :hmm
1. Not enough water, I tend to underwater because I fear rotting the roots.
2. Low Humidity, it is between 30%-50% inside at the momment.
3. Low Temps, at night it was getting down to arround 57F or maybe slightly lower and only goes up to arround 66F (maybe slightly higher) morning and evening. Recently (last 3-4 days) we have kept it at a min of 63F.
4. Temp swings, as above it was swinging between 57F and 63F until the last few days.
5. Not enough light, the room they are in is only getting light from an east window at the end and with the dark days we are having there is little light coming through that. Once the Christmas Decorations are down there will be a window in the west as well and the room is noticably brighter, but the tree is in the way of that window.
6. Something else.

There are pics below of the plant now, and of it's roots. The roots on the outside of the mass seen to be in good condition and there are a lot of them.

http://lh3.ggpht.com/_o4OXVkcS2VU/Sz...%20%283%29.JPG http://lh6.ggpht.com/_o4OXVkcS2VU/Sz...%20%284%29.JPG http://lh6.ggpht.com/_o4OXVkcS2VU/Sz...%20%281%29.JPG

HI Rosie! Your Milt looks good. It looks like the first pic has an old stem, so perhaps that is just an old section of the plant. It could also be too close to window. Was the leaves touching the glass? I would also suggest not letting the plant completely dry out. I keep mine moist, but not overly wet. Mine get to 55 during the night, and bloom fine, so I don't think it's the temp. (no draft, though). I don't have much humidity in winter either, so I don't think it's that. Light should be more. And don't over-fertilize as they don't like that. Roots do look good.
So maybe I'm wrong, but I would say to increase light, and keep roots moist. It looks like you have lots of new blooms coming!
Oh and Oncidiums like alot of light also. Hope that helps! :)

I'm voting on #6-something else. I think what you are seeing is perfectly natural. Outer leaves usually drop first on older backbulbs. It might go on for a while as the plants "sucks in" all the nutrients from the outer leaves before getting ready to send out the next flush of growths. Roots look good. Just my 2 pence.

Thanks Kiki & Ross.

It's not been by a window and nor have the others doing something similar. I probably have let it dry out too much and I think I'm going to give it more light as it is probably not getting enough.

Ross, I have wondered if it was just natural, especially on the others which are just loosing one or two outer leaves, or just a leaf on an old back bulb. I think if it was not for this one I would not have been worried about the others.

I think I was most worried about this one because there are four leaves on the front p-bulb and one on the back p-bulb that are all turning yellow/brown and it seems like what was quite a large plant will soon end up with very few leaves left.:(

I wonder if the plant has over stretched it's self. It had one open spike of flowers when I bought it and 3 spikes of buds. It has then grown another 2 spikes as well giving a total of 6 spikes in a couple of months. The open flowers are on the fourth spike and they have not opened fully and are paler, a couple of buds on the last two spikes have dried up and not developed.

There is no sign of new growths which worries me, I would like to see it growing but hopefully that will come :crossfing

Look closely at pic #1. You'll see a pseudobulb forming in between the leaves (the top is just peaking out). I believe that yellowing is natural.

Thanks King,

Yes there is a p-bulb forming in the center of the fan of leaves. The second fan of leaves also has a buldge which is probably a p-bulb starting (there is also one back-bulb).

While I was expecting the p-bulbs to eventually lose their leaves I was suprised by how many were going at once and as I'm not yet used to these I was getting worried.:blushing:

Well...

Eventually, on each shoot, you'll only end up with the leaves that are on the pseudobulbs proper. All the others will slowly die back as the pb's mature.

Yup. Only the leaves actually attatched to the top of pseudo bulb are intact once the bulb is older.

Thanks everyone. I'll get used to these soon. :)

Mine do the same out with the old in with the new :)