Yellow spots on leaves

[starwave]

Hello, does anyone konw why there are yellow spots on leaves?
It started at the beginning of the fall, when temperature suddenly dropped. Since then the light has been much less, moss has dried much slower and air circulation was not good because air conditioning was not on. I am thinking one of them is the reason or may be combination of those?

I just bought a plant light to give extra 4h light per day.
As it is getting colder, heat will be turned on.
And I am watering less amount.

Not sure what else I can do.

[estación seca]

How cold? What is the daylength?

[starwave]

Originally Posted by estación seca

How cold? What is the daylength?

It’s about 45-65 outside. Inside it’s abou 66 at night and 70+ during the day.
Day length is about 10h.

[sweta]

Originally Posted by starwave

Hello, does anyone konw why there are yellow spots on leaves?
It started at the beginning of the fall, when temperature suddenly dropped. Since then the light has been much less, moss has dried much slower and air circulation was not good because air conditioning was not on. I am thinking one of them is the reason or may be combination of those?

I just bought a plant light to give extra 4h light per day.
As it is getting colder, heat will be turned on.
And I am watering less amount.

Not sure what else I can do.

Wonder if its mesophyll cell collapse or could be some kind of fungal disease. Maybe you could just cut the portion of the leaf thats damaged and dab some cinnamon on the cut portion. If its some kind of fungal disease due to humidity then cutting off the leaf will stop it from spreading. But if its mesophyll cell collapse then I'm not sure if there is a remedy for it.

[estación seca]

It looks like cold water hit the leaves. Your temperatures are not impossible for Phals but are low.

[Roberta]

I agree with ES. Don't cut... I think that you just need to correct the culture (warmer and drier) and it won't progress. The leaves are need for photosynthesis to support the plant. Keep an eye on it, the spots won't go away but if the conditions are improved, likely won't spread.