What is acordian wrinkles in leaves caused by?

[Kaschmitz]

I have a couple of Oncidiums with pleats in the leaves ay the base. Was wondering if it is caused by too much fertilizer?

[estación seca]

The opposite - not enough water. Oncidiums are famous for telling you you're not watering enough.

How big are the plants? What are they potted in? What are your day/night temperatures? How are you watering?

[Kaschmitz]

I had increased the watering and fertilizer a few weeks ago during summer. Temps are between 78 -83 daytime. I do not put them outside. They have a couple of mature
pseudobulbs.
Thank you for your help.

[SADE2020]

Lack of water :

[3rdMaestro]

I'm finding that oncidiums like more water than you might think. The only way I could get my oncidium twinkle plants to stop pleating was to put them in a shallow saucer (like a half inch or less deep. In a pinch, just use the plastic lid from a food product) and keep the saucer filled with water.

[Shadeflower]

It's not a lack of water, a lack of water causes leaves to either wrinkle or flop. Accordion leaves are caused for a different reason but since everyone believes it is lack of watering I will just go along with it for the sake of my sanity even though not every problem is a lack of watering and I certainly would not start overwatering my orchids with acccordion leaves.
I've given up caring lol. Let there be soggy swampy accordion growing orchids everywhere.

[Fairorchids]

@ Shadeflower:

Since you obviously know better than everyone else, perhaps you should state your qualifications for making those statements.

I have been a commercial grower from 1968-1977, and again since 2013. I agree 100% with the postings prior to yours, Oncidium/Miltonionopsis showing accordion pleats are 100% asking for more water. Those orchids do NOT want to dry out, EVER!

[camille1585]

Shadeflower, it is actually common knowledge that Oncidium types will pleat when they don't have enough water, either chronically underwatered or had a short dry spell during active growth. If we were talking about Phals for instance, then yes, I would agree with you that lack of water will lead to wrinkled or floppy leaves.

A note to the OP, once the pleating has appeared, it is permanent. You will know if you are watering enough if the bulbs stay plump and wrinkle free and if new growths come in wrinkle free.

I do the same as 3rdMaestro and often leave a bit of water in the saucers of my Onc types, and once the saucer is empty, I'll wait 1-2 days (depending on temps) before watering again (only in the warm growing season, in the winter I let them dry out more and never leave standing water).

When I was a newbie orchid grower I was always killing Oncs. The roots were dying so I thought I was overwatering even though the pleated leaves were screaming for more water. Turns out they were dying from being too dry, and once I got over my fear of overwatering Oncs, I immediately started having success with them. They did even better once I started repotting in fine bark instead of medium grade (note, what works in my conditions might not work for everyone!).

[Kaschmitz]

thank you.