Why are my oncidium leaves going yellow green

[Mercurianmad]

Hey there I have an oncidium. it looks very sad in the pictures but that’s just because it’s a rescue.

It is growing six new roots so it will look better shortly. it’s leaves are going more yellow green in places and I’m wondering if it’s too much light?

I added an extra layer of cheese cloth in the window to try and defuse some more light for it. What do you guys think?

I have it potted in lava rock. Humidity is around 50%. I let it dry out before I water it but that happens pretty quickly. it usually gets watered every day or every other day.

[rbarata]

Is it possible to post a better/closer photo with more light?

[Mercurianmad]

How’s this?

[SouthPark]

M.M. that setup looks quite ok actually. Just maintain some gentle air-movement in the growing area. And keep the light intensity around 'medium' - just like that --- no direct sunlight for now. And don't let the orchid get too cold. Regular room temperature iis good.

Waiting for drying out is no problem. My oncidium roots dry out all the time. Keeping their roots lightly moist is ok too. Avoid getting the regions too soggy wet for long amounts of time, especially at the bulb.

Growing new roots is terrific news. Just let it keep growing now, and allow it to just do its thing now. Sounds good anyway.

As for less green leaves. More light can certainly to that sort of thing. And it's not necessarily bad too. As long as it doesn't get overly yellow, then that's quite ok.

Also - if the window gets too warm due to sun energy heating up the window, and it feels real warm or too hot there, then watch out for that kind of thing too, otherwise a plant can broil or get slight cooking.

And ----- every once a while - eg. monthly, or 2 times a month -- give the orchid some weak fertiliser (liquid form ... mixed with water), and also cal-mag (weak). This is so that the orchid gets some needed elements, fertiliser ----- for ensuring the photosynthesis process keeps working nicely.

[KingKong]

I find oncidiums are very easy so they are a lot more forgiving when it comes to watering or the media.

Southpark mentions a gentle breeze, as with most orchids a fart a day should be plenty.

I have my oncidium in self watering pots that suck water through a wick that then hydrates either lava stones or clay pebbles. They only need to be topped up with water once a month like that.

I would not personally pot the bulbs that deep, they could rot more easily like that, I know how wobbly they can be if you don't but it is safer to pot it up higher, only cover the roots and hold it in place with sticks instead.

Lava rock dries out too fast for my liking but it works great with a wick. Worth thinking about.

[Ray]

The yellowing of the leaves appears to be primarily on the older pseudobulbs, so is an indication that the plant is extracting nutrients from them and diverting them to growing new tissue (probably roots, in this case). Unless it is happening more broadly, I wouldn’t be too concerned.