I am having some stains on the area as shown in the picture. I only have 2 oncidium plants and it happens to both plants. Any idea how to prevent this? It doesnt happen when i pot them in charcoal. It happens only after i migrate it LECA.
I think it's fungal. From what I can see. Try some Thiomyl solution and repot. Apparently this plant doesn't like LECA. Some don't ever adjust to it while others do.