Why Are My Plant's Leaves Turning Yellow or Falling Off?

Updated on May 30, 2017
Yellow Hibiscus Leaf
Yellow Hibiscus Leaf | Source

What Causes a Houseplant's Yellow Leaves?

So you have discovered that your houseplant has some yellow leaves or may be losing leaves, and you want to know why. The shortest and most common answer is under-watering.

Think of your plant as being a company, its leaves as workers, and water as wages. If the company runs short on money, it has to lay off some workers because it can no longer afford to pay them. Like any smart company, a plant will always lay off the least productive workers first, which are those leaves that are nearest its base. These leaves are usually the oldest, sometimes smallest, and have not gone that extra mile in search of more light and or water. They are not the innovators of our little corporation.

But there are other reasons for yellow leaves.

Troubleshooting Yellowed Leaves

  • When a plant is under-watered, it reduces the amount of resources sent to the least-important leaves. When you water, the plant may recover, but damage has already been done.
  • Some plants react to changes in watering slower than others, so some will show symptoms of distress within a week, others can take several weeks to display signs of a problem.
  • Sometimes, the yellowing will show after the plant has received the proper amount of water. I call this "rebound yellowing." It can confuse you because the damage appears when the plant seems otherwise healthy. You might think the plant is still lacking water and water again, causing over-watering.

In general, if the yellow leaves on your plant are solid yellow and fall or pull away from the plant easily (depending on the plant type), you have under-watered at some point in the past. But if the leaves on your plant display stipled yellowing or mosaic yellowing, or appear yellow or light green with dark green veins, and if the leaves are still well attached to the plant, then you probably have another issue.

Other Causes of Yellow Leaves

  • Spider mite. What's this: Webs? Why does my plant suddenly look like it belongs in a haunted house? If any of this sounds familiar, you may have spider mites.
  • Chlorosis, which is caused by an iron deficiency. Chlorotic plant leaves will be very light green or yellow and have very deep green veins. You may also notice new growth that is a faded, washed-out green.
  • Over-watering. Generally, this yellowness will appear in a mosaic pattern, not solid yellow, and the leaves may have unsightly, crunchy brown tips but will not fall off easily.
  • Seasonal changes. Yes, some indoor plants will react to changes in season. I have seen this happen with Ficus trees.
  • Chemicals. Some plants react badly to chemicals in the air like paint fumes and floor treatments. Plants affected in this way will drop their leaves, which may or may not turn yellow. In my experience, Ficus trees are highly reactive to chemicals as well.
  • A new environment. For a newly purchased plant, this is common. Most plants are grown in ideal conditions and then moved out into homes and offices that generally have much less light and airflow available. This is cause for a layoff of leaves. The plant will stop once it regains balance in its new environment.

Preventing Yellow Leaves on a Houseplant

  • The most common scenario is just forgetting to water the plant. If that is your problem, then you may want to make yourself a watering schedule (I suggest weekly) to check the plant for moisture and water accordingly.
  • You may need a saucer to hold a little excess water to get the plant through the week, especially if it is in an area with high light or heavy air flow.
  • Beware of the danger of over-correction—that is, turning from an under-waterer to an over-waterer. There is a balance to be met in plant care as with many things in life, there really is some skill involved in caring for a houseplant.
  • If all else fails and you have the funds, there are watering services available. Consider hiring someone to take care of your plants for you.

Remember this: Some yellowing of leaves is normal, especially if you have a new plant acclimating to its new, lower light environment. If you see yellow, it does not necessarily mean your plant is doomed. It merely means that the plant is sending out some signals that something has happened or changed. Let the signals teach you.

Questions & Answers

    Been a bit too thrifty with water application? Your thoughts are welcome here.

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        Linda Solomon 5 months ago

        My. Tomato. Plant. Turn. Yellow. But my Tomato. I'm getting Big and four of five on one Vine. They making. A lot of tomatoes and a few lives are yellow. Thank maybe Put tell me what to do