A houseplant’s leaves can turn yellow for lots of reasons, which can be pretty frustrating for new plant parents because it isn’t clear right away what the problem is.
Today we will discuss the most common reasons that a houseplant’s leaves turn yellow and how to determine which is afflicting your plant so you can prevent more yellowing.
Table of Contents
- Older leaves closer to the potting mix are turning entirely yellow
- Old AND new leaves are turning entirely yellow
- Many leaves are fading in color and yellowing
- Related Posts
Older leaves closer to the potting mix are turning entirely yellow
If the older, more mature leaves are turning yellow, there are several reasons this might be:
#1 If it is just one or two leaves, it could be that those leaves are old and have reached their retirement age. Nothing is wrong with the plant. It is doing what most plants naturally do and dropping the oldest leaves
What to do about it: Nothing! Your plant is doing just fine. 🙂
#2 If it is several leaves or if the plant is consistently yellowing older leaves, it could be that the plant isn’t receiving enough water to sustain all of its leaves so it drops the oldest leaves first
What to do about it: Check the plant more frequently to see if it is ready for watering and ensure that you water it thoroughly when it is thirsty.
Need help determining whether your plant is ready for water? Click to read a post all about it.
To water thoroughly, ensure water saturates the potting mix and runs through the drainage holes before moving on to the next plant.
Dump any water that accumulates in the drainage tray or cachepot to prevent the roots from receiving too much water.
Old AND new leaves are turning entirely yellow
#1 If it is several leaves, both old and new, it could be that the plant is staying wet for too long and is developing root rot.
How long should a houseplant stay wet? Most houseplants should not feel super wet after a day or 2. If the surface of the houseplant’s potting mix is still super saturated after a couple of days, your plant may be staying too wet.
Here are some possible reasons why your plant is staying wet for too long:
- The plant isn’t receiving enough sunlight to use water in a timely manner
- The plant is receiving water too frequently and isn’t allowed to dry out enough between waterings
- The plant is potted in a soil mixture that is too dense which is retaining too much moisture
- The plant is in too large of a pot for the size of the root ball
If you aren’t sure which of these issues it might be, here’s some guidance to help:
Is your plant more than 2 feet from a window? If yes, try moving it closer to see if that improves the situation. Plants in the interior of your home aren’t likely to do well because light diminishes quickly as you move away from the window.
Does the potting mix your plant is in look like one even color? If so, it might be too dense. Houseplant growers often use dense mixes in their greenhouses because the greenhouse is kept well-lit and at high temperatures so the plants dry out super quickly. Our homes aren’t nearly as bright or hot, which means the plants aren’t drying out nearly as quickly which can cause the conditions to remain too wet for the roots to stay healthy.
Try repotting the plant into a potting mix that has perlite or pumice in it to increase drainage. Most plants will do well in a mix with two-thirds standard houseplant potting mix and one-third perlite or pumice.
If you check the potting mix, is it already wet? If you didn’t just water the plant and it is super wet, then the mix might be too dense or the pot might be too big.
How do you know if the pot is too big? You have to remove the plant from its pot and see how large the root system is. If the root system is smaller than about 2/3 of the pot size, the pot might be too big.
If various leaves, especially newer growth, are developing yellow dots or patches, it might be a pest
#1 When leaves develop yellow spots or patches, particularly on new growth, it is typically due to some type of pest. Most often, it is a result of spider mites or thrips.
Here’s some posts to help you identify whether you are dealing with a pest:
What Pest is on My Houseplant & What Can I Do About It?
How to Identify and Eliminate Thrips on Your Houseplants
How to Identify and Control Spider Mites
#2 If the yellow patches have a brown center, this is often a fungal pathogen infecting the leaves of your plant
The easiest way to treat a fungal pathogen is to remove any severely affected leaves and apply a fungicide to the plant per the instructions on the bottle.
If your plant is in a space surrounded by other plants with little air between them, spacing out your plants can help to prevent fungal issues as well. Some people will also run a fan on low to increase circulation.
Fungus loves a humid, wet, stale area so the better the airflow is the fewer issues you should have.
Plants that are underwatered can also develop fungal issues. This happens because their leaves develop cracks similar to what happens to our human skin when it becomes extremely dry, which provides vulnerable areas for fungal and other pathogens to infect the plant.
Many leaves are fading in color and yellowing
If the leaves are fading in color and yellowing, it is often caused by either too high light levels (which can bleach the leaves) or nutrient deficiency.
Is the plant is more than a couple of feet away from the window? If yes, it’s very unlikely to be too much light and could be nutrient deficiency.
Have you fertilized your plant regularly and/or repotted your plant within the last 2 years? If no, it is very possible it is lacking nutrients.
Need help with fertilizing? Check out these posts:
How to Fertilize Your Houseplants for Beginners
How to Identify 7 Types of Nutrient Deficiency in Houseplants