Leaves have orange crystals clinging to the plant hairs . This symptom will be most visible on the crown. This is called Leaf Tip Burn, and it is brown in color. Leaves darken . They appear brown or black in color.
Plant growth is slow .
Treatment Remove any rotting leaves or stems. Rinse the plant and pot with lukewarm water. If you see orange crystals on the leaves or other concentrations of fertilizer salts , rinse long enough to dissolve and wash away these crystals. Drench the soil with lukewarm water, and let any excess water drain from the pot. Wait one week before fertilizing, again.