Moisture
The most common cause of yellowing leaves among Rhaphidophora plants is improper soil moisture—in particular, overwatering. Only water your Rhaphidophora when the top 75% of the soil in the pot is dry. In the winter, you can allow your plant to dry out a little more between waterings, but be sure to boost humidity with regular misting, a humidifier, or pebble tray.
When you water your Rhaphidophora, make sure you provide enough water so that liquid flows from the drainage hole at the bottom of the pot and into the saucer. It’s extremely important to discard any excess water in the saucer and to not let your plant sit in standing water. Your Rhaphidophora will not respond well to “wet feet,” which causes the roots to rot and the eventual death of the plant.
Humidity Level
Low humidity and dry soil cause leaves to droop and brown on their edges, later followed by entire yellowing. Use a humidifier, add a pebble tray, or mist your plant often.
Improper Light
Rhaphidophora will grow best when placed in bright indirect sunlight. When exposed to direct sunlight for too long, the foliage can burn. While Rhaphidophora can adapt to low light areas, their growth will slow. If placed in very low light, yellow leaves may develop.
Pests
A weakened or stressed Rhaphidophora is more susceptible to insect infestations. Sap-sucking bugs like spider mites can drain your plant of moisture. This problem quickly manifests itself by yellowing leaflets and fronds. Scale, mealybugs, and spider mites occur frequently in indoor conditions. If not killed early on, these small pests proliferate and move all along frond parts into nooks and crannies. The piercing mouths of the insects exhaust your plant and accelerate yellowing, especially if your plant is already unhealthy from poor lighting, a nutrient deficiency, or improper soil moisture.
Some yellowing is natural
Is your Rhaphidophora pushing out new growth? If there is new growth on your plant and the yellowing leaves are older, particularly at the bottom of the plant, this yellowing is natural. Your plant sheds its old leaves and sends energy to new growth.
