My mexican fan palm is in a pot right know , with the palm itself being at about 3 1/2 feet tall. Currently the palm has been getting yellow on the tips of new fronds and the old fronds are turning a brown and yellow color in the middle. And the tips on one frond is all dry and crispy like. What does all of this mean? Oh and why could it be my palm isnt growing much in the past year? it has only opened up maybe 2 fronds and has not grown at all. It is outside in full sun. does this palm need humidity?