Leaf Spotting and Yellowing in Miltonia

[paulopinto]

Hi there, recently I was gifted this miltonia orchid that started to develop this leaf spots and yellowing. I've read that oncidiums are prone to this but I would like to know if you think this is a pathogen/pest or some culture problem (stress-related or something) and what can I do to improve/prevent this from developing.

[estación seca]

This kind or orchid has flowers that look like pansy flowers (Viola spp.) It has been separated from genus Miltonia and is now called Miltoniopsis.

They require cool but not cold temperatures, high humidity, lots of water, good air circulation and bright light, but not direct sun. They can be difficult to keep in homes with heat. In the US they are not difficult right on the coast in southern California and in San Francisco. Just a few km inland they become difficult due to heat and low humidity, or too cool temperatures in winter.

[paulopinto]

Thanks for the insight, but that doesn't answer my question tbh. I live in a Mediterranean climate (quite similar to the climate in California I believe) Average temperatures are 25-27 C in the summer and 10-14 C in the winter. As for humidity, it usually stays at 80% in the winter and 65% in the summer. I keep the plant away from direct sunlight but on a bright room.

[estación seca]

It probably needs more water and pure water, like rain or reverse osmosis. If the medium is old it could be repotted when it is making new roots. I would use a new pot with 4cm larger in diameter and fine orchid bark for medium. Don't remove all the old medium; shake off what is loose.

[paulopinto]

Thanks, and just to be clear, you wouldn't use sphagnum moss? just fine bark?

[estación seca]

Sphagnum moss could also be used.