mediterranean fan palm tree care
It could be many different factors. Magnesium deficiency could be one, lack of sun light like you said could be one. Manganese deficiency also could be one. I don't think potassium deficiency would be it. Try watering it a bit more, and adding some Magnesium. You will not see a difference right away but in the new fronds you will. Add some Nitrogen also. This will keep them a bit greener. Other indoor palm trees would be pygmy date palms, sago palms, cardboard palms, pony tail palms and kentia palms, oh and bamboo palm trees.
Hope this helps.
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