The 5 Most Common Reasons Why Your ZZ Plant Has Yellow Leaves


Why are the leaves of my ZZ plant turning yellow?

This is one of the most common questions that people ask when they notice their ZZ plant has yellow leaves.

ZZ plants (Zamioculcas zamiifolia) can be a beautiful addition to your home, but if you notice that the leaves on your plant are starting to turn yellow, it could mean there is a problem with how well-cared for they are. While this might not seem like a big deal at first glance, knowing what causes this and how to fix it will help ensure that your plant stays healthy and vibrant.

If you want to avoid having problems with your ZZ plants in the future, then understanding why their leaves turn yellow is key.

That’s where we come in – read on below and learn more about why this happens so you can keep them looking great! 

Why is my ZZ plant turning yellow?

There are a variety of potential reasons that could be causing the leaves to turn yellow and you need to actively investigate what that reason is, so you can decide on the best course of action to take.

When doing this, you need to consider the plant holistically and think about the essential components required for successful growth, namely soil, lighting, feeding, and water.

Here are the 5 most common causes:

1) Overwatering

Your ZZ plant is similar in structure to the cactus or succulents in that it does not require a lot of water.


If you tend to be heavy-handed with the watering can, be extra cautious with this plant. Too much water will cause the roots to rot, which will in turn lead to yellow leaves.

You can quite easily find out if this is the reason. 

Simply by inserting your finger into the soil to feel if it is moist or not.  If you aren’t sure if it’s dry, wait another day or two. It is better to underwater a ZZ plant than to overwater it as it will bounce back quite readily. 

To be accurate you can use a soil moisture meter which will tell you immediately.

A general rule to follow is to water once every week to two weeks during summer, and every three to four weeks during winter, making sure that the soil dries out in between waterings.

After you have watered your plant, toss out any water that drains through the soil and flows into the saucer; you do not want your ZZ plant sitting in a permanent water source.

2) Poorly draining soil

The soil that you use for your ZZ plant goes hand-in-hand with the watering as it must have excellent drainage. 

The best soil to use is a succulent mix.

You can supplement this with a handful of coarse perlite or orchard bark, or even horticultural charcoal will work. Do this and you will have excellent well-draining soil that your plant will thrive in.

In addition, ensure that the pot you choose has sufficient drainage holes. You need the water to drain away quickly otherwise the roots will start to rot.

Be wary of adding coffee grinds to your plant because it ends up creating a superfine mulch on the top that traps water. This will also lead to root rot so it would be better to toss your coffee grinds into your compost heap if you prefer organic fertilizers.

3) Underwatering a ZZ plant can lead to yellow leaves

There are a few ways your ZZ plant might indicate it is thirsty and it is time to be watered – look out for yellow leaves, dried leaf tips, dropped leaves, or shriveled stems.

Your ZZ plant, as tough as it is, does still require some water.

Water it sparingly and don’t flood it. Allow the water to drain away completely and remove any excess water from the saucer.

4) Rootbound plant

ZZ plants do not like to be root bound. 

Because they do not have roots as you would normally see on other plants and they have rhizomes that are similar looking to bulbs, they need space to grow as the plant matures.

If there is insufficient space to grow, the chances of root rot and fungus increase. If your ZZ plant succumbs to root rot, water will not be transferred around the plant and the leaves will discolor.

It is advisable to re-pot your plant every two years into a pot that is one size larger than its current home.

5) Too much direct sunlight 

The ZZ plant thrives in low, or indirect light, which is why it makes a perfect indoor houseplant.

This is also why they grow so well under fluorescent lights in shopping malls and commercial spaces.

Your plant can successfully receive morning sun, but the harshness of the afternoon sun will potentially scorch its leaves, turning them yellow-brown and causing them to wilt.

If this happens, move the plant to a dimmer area and keep it out of direct light.

Root rot causes a ZZ plant to have yellow leaves

Root rot, caused by a few reasons, is usually why the leaves of your ZZ plant will turn yellow. It is because the rhizomes under the ground that store the food and water begin to rot.

When root rot happens, they are unable to absorb oxygen and will not be able to send water and nutrients to the rest of the plant and this will be reflected in the discoloration of the leaves, in other words, the leaves will turn yellow.

There are a few reasons why the roots might rot causing the leaves to turn yellow, the most common one being overwatering. 

Lastly, there could be a fungus lying dormant in the soil and after one or two heavy waterings, they could become active and attack the roots.

How to save your ZZ plant if it has been overwatered

Yellow leaves are a sign that your plant is distressed, and you will need to act swiftly to save it.

Follow these simple steps to save your plant:

  1. Check to see if the soil is damp or dry. Remove your ZZ plant from its pot, dust the soil off the roots and inspect them.
  2. Healthy roots will be sturdy and white, while roots with root rot will be mushy and brown. Using clean pruners , carefully snip away the portions of root rot. Clean the pruners between cuttings so as not to spread any fungus.
  3. Cut incisions in the healthy roots to encourage new root growth.
  4. Repot your plant into a pot with good drainage and use new soil. Discard the contaminated soil.
  5. Ensure the soil is damp but not wet and allow it to dry out completely before watering it again.
  6. Once dry, prune back the yellowing leaves and any droopy stems, which are another sign of overwatering.

Conclusion


There are a variety of potential reasons that your ZZ plant has yellow leaves and you will need to investigate to find out what the reason is:

  1. Overwatering your ZZ plant
  2. Poorly draining soil
  3. Underwatering your ZZ plant
  4. Rootbound
  5. Direct sunlight


The most common cause is overwatering.

These plants do thrive on neglect so once you have selected a pot, mixed up a fast-draining potting soil, and set it up in its own space, you only need to water it every couple of weeks when the soil is dry.


Keep your plant in low light and in temperatures between 70°F to 90°F. 


Do these things and your ZZ plant will thrive!

About the author 

Paul - Better Houseplants

Loves orchids and foliage houseplants. Always trying to be a better plant parent. Let's get growing!

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