Cattleya Hybrid with Mottled leaves.

[BrassavolaStars]

Hello All,

I have a cattleya orchid hybrid, a Ctt. Chocolate Drop "Kodama" that seems to have strange chlorotic spots on the leaves. I do not know when this occurred.

The plant has been outside since around May. I never closely inspected this plant and it may have had the spots always. I got it online several months ago (around March).

Aside from the spots, the plant seems healthy. The new growth as pictured does not seem to have any issues with color break.

I was concerned the spots could be viral and infect my other plants.

[rbarata]

Probably magnesium deficiency.
Use epson salts with your water (1 tsp/gal) for a while (1 month, for ex).
While you do it, suspend your fertilizer (reactions may occur between the fert and the salts, creating unwanted salts in the medium - might change its ph - and diminishing the efficacy of the "treatment").

[Ray]

While I agree with Rui about the likelihood of it being a magnesium deficiency (that might not be it, but that's the easiest to treat), I don't think you need to worry about adding it to fertilizer at all. Epsom Salts is somewhat unique among fertilizer additives in that it really doesn't affect the pH nor react with other fertilizer ingredients.

A tablespoon/gallon, one time, should have an impact within a week or so - maybe sooner.

If you can tell us about the watering and feeding it has (or hasn't) been getting, maybe we can help more.

FWIW, I had a couple of phalaenopsis plants living on my deck that got watered with our yard irrigation system, so I rarely had to water them by hand. That meant, however, that I didn't feed them as often as I did the rest of the plants, and with my water supply having almost no magnesium, it became an issue. Once I relocated them and resumed feeding them regularly (K-Lite has 3% Mg), the mottling went away.