It can be demoralizing when the leaves of any houseplants turn yellow. But it happens. And when you spot yellow leaves, it’s a signal that your plant is ailing.
If you notice yellow plant leaves in time, there are steps you can take to save them. But first, you need to identify potential causes. Some of the most common include overwatering, underwatering, extreme temperatures, inadequate fertilization, and light levels that don’t suit the plant.
What does it mean when a houseplant’s leaves turn yellow?
Aaron Steil, a consumer horticulture extension specialist at Iowa State University, says that yellowing leaves is “one of the vaguest and most difficult issues to deal with because it can be caused by a wide variety of issues.” Furthermore, leaves turning yellow isn’t usually because of one single problem.
More often than not, there are several factors that combine to cause a change in color. Sometimes the leaves will turn brown as the condition deteriorates, and then they drop.
What this means is that you need to identify the problem because you can be sure why your plant is turning yellow.
Reasons why houseplants leaves turn yellow
There are several common reasons why the leaves of houseplants turn yellow. One common reason is moisture stress from too much water.
Another common reason is too little water. Too little light and normal aging also make indoor plant leaves turn yellow.
Even repotting plants can turn some leaves yellow. Let’s look at some of these reasons in a bit more detail.
We all get old, and so do plants.
The horticulturists at Mississippi State University call this shading because as plants mature, the leaves at the bottom of the stem get heavily shaded. Then they turn yellow as they continue to “senesce” or age.
Natural aging isn’t an indication that anything is wrong. The yellowing leaves simply aren’t productive anymore.
It’s best to remove the yellow leaves to improve air circulation.
Extreme heat and extreme cold can both be the cause of leaves turning yellow. This may be because the temperature in the room is too hot or too cold.
But it’s more likely to be due to blasts of hot or cold air from air ducts, doors, or windows. Sudden temperature variations can also be very damaging.
Often plants develop yellow leaves because they have been under-fertilized. If you pick this up quickly enough you might be able to reverse the yellowing.
Both insufficient nitrogen and potassium levels often cause yellow leaves, though potassium deficiency appears more commonly as yellow leaf margins.
If you see yellowing between the veins, this is more likely to be from too little magnesium.
The leaves of most plants will turn yellow if you give them too much water. This will be compounded by insufficient drainage.
But moisture stress is also due to too little water. It’s pretty easy to identify moisture stress by checking the soil.
Not enough light
When plant leaves turn yellow from a lack of light, you will usually see that only the side turned away from the light source is affected.
How do you fix yellow leaves on houseplants?
The action you need to take to fix yellow houseplant leaves depends on the cause. But be aware that most of the time, you’re going to lose the yellow leaves.
Once an entire leaf turns yellow, it’s best to remove it. However, if you fix the problem, new green leaves will start to grow.
Here are some common remedies, most of which are largely common sense. For instance, if you identify that your plant turning yellow is in a draft, move it.
Moisture stress is a very common reason for leaves turning yellow. Luckily, it’s also very easy to rectify.
If your soil is very dry, you’ll need to give your plants more water. Try bottom watering to direct the water into the roots. Just don’t overdo it.
If your soil is soggy, you’re giving your plant too much water. Be warned that it won’t stop at yellow leaves. You’re also inviting root rot.
Fixing a plant that has yellowing leaves due to a lack of light can be super simple. Try turning the pot once a week so that all sides get access to light over time.
Alternatively, you might consider moving the pot to a sunnier spot. If your interior is dark and there’s nowhere to put the plant where it will get natural light, consider an artificial grow light bulb. They’re easy to find and surprisingly inexpensive.
If you haven’t been feeding fertilizer, a well-balanced product will likely do the trick. Bone meal is a good slow-release fertilizer that is rich in nitrogen and phosphorus. You can also add compost to the pot by digging around the plant first.
If you suspect magnesium deficiency, you can try spraying with an Epsom salt and water solution. Epsom salt is magnesium sulfate, and all you do is mix two tablespoons with a gallon of water.
How to prevent yellow leaves on houseplants
Knowing why your houseplant leaves might turn yellow is the first step in preventing this from happening. For example, if you have a peace lily in a pot indoors, be aware that the most common reason for the leaves turning yellow is incorrect watering.
These plants are also very sensitive to direct sunlight, which will quickly turn the leaves yellow. Peace lily leaves also tend to turn yellow after repotting.
This is often because larger pots contain more soil that dries out more slowly after the plants have been watered. Too much moisture can also cause root rot.
If you are asking why are some of the leaves of your indoor plant turning yellow, take the time to work through the possibilities. Sometimes the reason suddenly becomes obvious. Other times, you may need to experiment with remedies to see if any of these help it improve.
It can be especially challenging when there are multiple problems or even just a bunch of possibilities. Start by looking out for the most common reasons that indoor plant leaves turn yellow.
Since moisture stress is very common, something to bear in mind when you water your plants is that they don’t all need the same amount of water. For this reason, it really does pay to get to know your plants.