My plant is dropping a few leaves along its stem that are down on the bottom and light never hits them, so they've stopped helping the plant to grow. I'm surprised it hasn't gotten rid of them sooner. At first the leaves turn yellow in a pattern, like a leaf from a ficus or some other exotic plant; then after a period of time, it's like the plant says 'enough is enough,' and the leaf turns brown and curls up, and is easily disposed of.