Natural Yellowing
It’s important to remember that the occasional yellow leaf is totally normal.
As your plant ages, its older foliage will eventually fade, turning yellow and then dropping off.
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Overwatering
One of the most common causes of yellow leaves on philodendron plants is too much water.
Overly wet, soggy soil can prevent the roots from taking up nutrients.
In severe cases, overwatering can lead to root rot, which can kill your plant.
Check the soilif it’s very wet,overwateringis likely the cause.
Stop watering and allow the soil to dry out fully.
ensure the pot doesn’t sit in water in its drip tray or cache pot.
Underwatering
Too little moisture can also cause philodendron leaves to turn yellow.
Your plant will likely look limp or wilted, and the oldest leaves will turn yellow first.
Give your plant a deep watering as soon as possible.
The best way to rehydrate the root ball is bybottom watering.
Place your plant in a sink or bucket and add water up to the plant’s soil line.
Low Humidity
In nature, philodendrons live in high-humidity forest environments in Central and South America.
They adapt relatively well to drier indoor climates in temperate regions.
However, too little humidity can cause problems, especially when combined with dry, neglected soil.
As their leaves release moisture through transpiration, they create a more humid microclimate.
The other method is to run a small humidifier near your plant.
Treat a pest infestation quickly to minimize the damage.
Quarantine the plant from the rest of your collection and treat it withhorticultural oilor insecticidal soap.
Calcium-richhard watercan also prevent your plant’s roots from taking up nutrients properly.
If the plant hasn’t had fresh soil for a few years, repot the plant.
If you’ve simply neglected to fertilize, apply a balanced houseplant fertilizer diluted to half strength.
Move the plant further away from the light source.
But the plant should be several feet from a sunnier south- or west-facing window.
You may also want to put up a sheer curtain to help filter and weaken the light.
Water when the top inch or two of soil has dried out.
Once plant leaves turn yellow, they’ll continue to fade, eventually dying and dropping off.
However, don’t remove more than 30 percent of the plant’s foliage at once.
