5 reasons for yellowing houseplant leaves (and what to do about it)

Houseplants do so much for our environment inside our homes. They bring a bit of the outside in. They are a wonderful addition to any décor. Most importantly they clean our indoor air. But many of us, even those blessed with a green thumb, have problems with houseplants—the most common of all being: yellowing leaves. 

Yellowing leaves are known as ‘chlorosis’. It occurs when something interferes with the plant’s chlorophyll (the pigment that gives plants their green color and helps create oxygen). 

Here are some of the causes, and fixes, for this issue:

Too much sun. Some plants can be yellow from the sun. Check online for information on your plants’ sun exposure needs. Then adjust your plants position or place in your home.

Overwatering. This is the leading cause of yellow leaves as we tend to “love” our plants to death. It’s characterized by yellow leaves that droop. Most plants need to dry out completely before the next watering. Then water thoroughly so the water comes out the bottom. Stick your finger in the soil to the second knuckle, the soil should feel dry before watering.

Underwatering. This can also lead to yellow leaves, although the leaves will have more of a crispy look rather than droopy. Water lightly then put the bottom of the pot in the sink or a bucket with a few inches of water. Let it sit for a few hours. The plant will naturally draw in the water from the bottom through the roots.  

Pot-bound plants. The next cause of an unhealthy plant can be a pot that is too small. Most plants will grow out of their pot eventually. With a pot-bound plant, the roots are too tightly packed and can’t sustain themselves. These plants will have yellowing all around rather than just a few leaves. To check, carefully ease it out of its pot. If the roots are circling around from bottom to top, it is pot-bound. A few roots sticking out the bottom or top are fine, you’ll know it when you see it. I once had a plant so pot-bound there was no soil, all roots! Of course, the solution is a bigger pot; go up one pot size, 2 at the most. Be prepared for the plant to lose a few leaves as it gets acclimated to its new pot. Just trim off any discolored leaves.

Normal growth. Even healthy plants will have old leaves that turn yellow and eventually drop. This is natural. The plant is getting rid of the old growth so it can put its energy into new growth. To know if that is what is happening to your plant, keep an eye out for new growth. If your plant is growing new leaves, it’s doing fine. Snip off any old and yellow leaves. 

Kathleen Weaver-Zech and Dean’s Team Chicago