Your orchid was thriving, but now it may need some support. “Why are my orchid leaves turning yellow?” you ask. Great question! The first step in Phalaenopsis orchid plant care is paying attention to the roots, leaves, and soil of your plant, which reveal a great deal about its health. Here are several possible explanations for your orchid’s yellowing leaves and what to do about it.  

Orchid Leaves Turning Yellow? Check the Light 

An orchid with yellowing leaves may have been exposed to direct sunlight. You may see a white patch with dark brown spots surrounded by yellow. 

Orchid Plant Care Tip: Although this tropical plant loves light, it prefers indirect sunlight. If you want to display your Phalaenopsis orchid on a windowsill, north and east-facing windows are best as they provide the least direct sun exposure. 

And if you don’t have windows facing in either of those directions, don’t worry. Orchids also do well in artificial light.  

Temperature Can Cause Yellow Spots 

Temperatures that are too low can also cause orchid leaves to turn yellow.  You never want to keep your orchid in a room under 60 degrees Fahrenheit. 

Orchid Plant Care Tip: Keep the thermostat set between 65 and 80 and your orchid will thrive. Avoid placing your orchid near open windows, fans and air conditioning vents as this will dry out your orchid. Remember, orchids are tropical plants, so they prefer humidity too, such as bathrooms and kitchens. 

Overwatering Can Lead to Yellowing Leaves 

Overwatering your orchid can lead to root rot, which could cause its leaves to turn yellow.

Orchid Plant Care Tip: If your orchid is suffering from root rot, repotting your plant in a fresh new potting medium will set it on the path to recovery. If your orchid still has some healthy green roots, trim the rotted roots with sterile scissors before repotting.   

Diseases Cause Leaves to Turn Yellow 

This is one of the more common causes of orchid leaves turning yellow. There are two types of diseases to watch for.   

If your orchid has a spotty appearance but smells fine, it’s likely a fungal infection. Typically, fungal diseases start out as yellow areas on the undersides of leaves. As these spots develop, they become visible on both sides of the leaf and turn brown or black. 

If you notice a foul smell, there’s a good chance your orchid has a bacterial infection. 

Orchid Plant Care Tip: In both cases, move your orchid away from other plants. Then, remove the infected area with a sterilized pair of scissors and spray the plant with a fungicide.