Why is my ZZ Plant Turning Yellow and Brown? | How To Fix it

Any number of problems might be causing the browning of your ZZ plant leaves. These might include issues around watering, pests, sunlight or even repotting stress. We’ll talk more about each of those in a minute. But first things first:

The ZZ  or zee zee plant – Zamioculcas Zamiifolia – has become an immensely popular houseplant in recent years. It’s size, ranging from half a metre to a metre – makes it a wonderful floor-standing addition to living rooms. The green leaves are known to be great purifiers, too.

 The plant is indigenous to Africa and may be toxic to cats but has been successfully propagated around the world. Unfortunately, some owners notice that the leaves of the plant turn yellow or brown, something that I recently had to deal with. This could be a sign of one or more problems. Let’s look into why this happens.

Why are My ZZ Plant Leaves Turning Yellow and Brown?

When you see your house plant leaves turning yellow or brown, look into possible causes immediately. Before any other positive action, though, do the following:

●      Find a good pair of shears or scissors. Rub the blades with rubbing alcohol.

●      Remove the brown leaves with the shears. Apply alcohol before every cut.

●      Be careful not to cut away too much of the plant. Any more than 20% could shock the plant.

Right. So, we’ve cut away most of the affected areas. Now it’s time to get down to causes and remedies and some basic zee zee plant care.

Causes of ZZ Plant Leaves Turning Brown and Yellow

In basic terms, ZZ leaves (like fiddle fig leaves and other house plants) will turn yellow and brown because of four main things: water, light, pests, and potting. Each of those has one or two sub-causes, but we’ll get into that. Let’s look at how we deal with each of these issues separately.

ZZ Plant’s Yellow Leaves Caused by Sunburn

Believe it or not, sunburn causes browning of ZZ plant leaves. ZZ plants come from Africa, so many people incorrectly assume that they are immune to extreme temperatures and sunlight. In reality, the ZZ can do quite well in dry conditions but struggles with hot temperatures and direct sun.

Your ZZ may be getting “sunburnt” if it has more than 4 hours of direct sun and heat. This is one of the first signs of your plant tips turning brown.

How to Fix It

This is an easy one. If you suspect that the direct light from the windows is too much, move ZZ to a corner with a little less direct sun. Don’t move it to the shadows because the ZZ loves light, just not too much directly upon its leaves. This should prevent the end of leaves from turning brown.

Inadequate Humidity

Yes, ZZ plants like a bit of humidity, and when they don’t get enough, they start to discolour. Moisture in the air (but not direct watering) helps to keep the leaves healthy.

How to Fix It

There are a couple of ways you can address the humidity issue:

●      Make a pebble tray: A pebble tray is a dish filled with pebbles or small rocks placed underneath the plant. Pour some water over the stones daily. When the water evaporates, it does so directly beneath the plant, humidifying the air around it.

●      Mist the leaves: Maybe it would be easier to use a spray bottle that emits a fine mist. Spray the leaves a few times a week with ordinary water. Be careful not to over soak the leaves, as this invites fungus and aphids. 

●      Make a bathroom break: Try moving the plant to the bathroom, if you have space and the bathroom has enough light. Not only will it make the bathroom feel exotic, but the humidity from the bath and shower will make your ZZ happy!

Over Watering

Sometimes, too much love results in plants turning brown. ZZ’s are used to drier conditions, and too much water can cause issues with rot and fungus. Note that improper watering isn’t simply a case of too much water. Inadequate drainage could also be causing too much moisture to remain in the pot.

Overwatering and rot will affect the root system. The rest of the plant will not be able to receive proper nutrients. This means the leaves will yellow or brown, and perhaps even die and fall off in extreme cases.

How to Fix It

The easiest way to find out is to check the soil. If the soil is wet, especially after the last watering, you may need to remove the plant from the pot to take a closer look. A general rule of thumb with ZZ plants: Allow the soil to dry out completely before watering again.

Check the roots. They should be white. If you see brown or discoloured areas, you may be seeing rot. Don’t panic – you may still be able to save old ZZ.

Use a pruner to cut away affected sections of the root. Do not cut away too much. When done, wash the pruning shears – residue fungus and rot can spread to other plants. Now repot into a pot that has fresh potting soil and better drainage, and keep an eye out for ZZ plant new growth.

Under Watering

Conversely, you could quite easily underwater the ZZ because its love of dry environments can be deceiving. As with most other plants, access to too little water will make it shrivel, lose colour, and eventually die.

How to Fix It

If you’ve seen a movie where someone is rescued from the desert, they always stop him from drinking too much water. The same principle applies. Start by giving a little water, and make sure the soil isn’t drenched. Also, make sure the bottom of the pot isn’t standing in water.

Give just enough water to dampen the soil, then keep checking to see when the soil has completely dried out. Repeat the process, and work out your watering schedule accordingly. You should now know how often to water the soil of your ZZ plant.

Incredibly dry soil

Somewhat related to underwatering, you may forget to dampen the solid from time to time, or forget that it will dry out faster in hotter months. When the soil gets too dry, the plant will droop or begin to discolour.

How to Fix it

In extreme cases, you may need to give the plant a particular “supervised” soak. Place the plant pot in 5-10 cm cool water in a basin or plastic tub without the drainage saucer. Let the plant soak up the water for 45 minutes.

When the dampness reaches the top of the soil, drain the tub and let the excess water drain from the plant. Afterwards, replace the draining saucer and put the plant back in its usual place. Think of it as a gentle spa day soak for your ZZ plant.

Pest Infection

All plants are vulnerable to pests. Aphids love to “drink” ZZ plant juice – or “sap” if you prefer. You can tell if your plant has aphid passengers by looking for small yellow spots. They especially love sitting underneath leaf blades.

How to Fix it

Fortunately, aphids aren’t especially difficult to remedy. You can make your own soap and water solution to get rid of them.

Mix two or three tablespoons of pure liquid soap in a small bucket of water. Spray the aphid-infected leaves (especially the bottom side).

Just be sure to not use any chemical detergents, which could be poisonous to the plant. Your local nursery may also have a solution for sale as an alternative. 

Nutrient Deficiency

Nutrient deficiency is a slightly more sophisticated issue, as it may be a try and test case. To explain: Nutrient burn is a side effect of over-fertilization.

To avoid this, make sure to only fertilize ZZ plants at most once per month. If you are using a soluble fertilizer, mix it to half strength.  

How to Fix it:

But if you have been overfertilizing your ZZ plant (more than once per month), you’ll have to take some action with the pot itself. Flush it out using plenty of water, or repot the plant completely. Use fresh new soil, and start a proper fertilizing regime.

Poor Water quality

However unlikely, your tap water may be causing your plants to turn brown at the tips and edges. Tap water is chemically treated and contains certain amounts of chlorine and fluoride that may be building up.

This is particularly relevant if you’re in a hard water area. 

How to Fix it

There are a couple of different approaches to work around the bad water issue.

1. Use a water filter – a basic container-based filter will do.

2. Fill a container with water and let it stand for at least 24 hours before watering your plants.

3. Use collected rainwater instead.

Transplant Shock

Is your plant suddenly not doing as well after changing pot homes? Plants can suffer some unnoticed or inadvertent damage when they are repotted. Also known as pot stress, it’s brought on by a repotting that’s been done incorrectly – even incorrect pot size.

Sometimes, owners use a new type of potting soil that doesn’t quite work as well. The transplant shock can be remedied with a bit of time. But it’s worth noting that avoidance is better than cure, and potting it correctly at the get-go will save a lot of stress and energy.

How to Fix it

Something a few casual owners realize is that repotting can take place at the wrong time. It might be nice to think that the plant can use a nice new pot for spring, but this is the wrong time to replant. Plants are sensitive before the blooming season.

As mentioned previously, different new potting soil is a common culprit. Try to keep using what’s working, whenever possible. Finally, don’t leave the plant unsoiled for longer than necessary. Roots that are exposed for too long will take damage.

If the damage has been done, the best you can do is to apply all the care in the world, and over time, your plant should show signs of recovery. Remember to remove already-damaged leaves and roots as you go along.

ZZ Plant Rust

Plant rust sounds nasty. But it is simply a particular fungal infection that actually affects lots of plants. Interestingly, the term “rust fungi” can be used to describe a number of different species of fungus. One type of “rust” won’t necessarily infect all your plants. Meaning… rust fungus tends to be plant-specific.

At any rate, you can tell rust fungus by the colour – a brown, rusty colour that starts out as small flecks but eventually develops into large bumps on the leaves, especially the underside.

How to Fix It

Plant rust can be a nasty customer to get away from. Remove all the infected parts immediately. It’s important not to use these for compost. Destroy them and throw them away. Next, wipe all the leaves gently to remove any traces of fungus that may have fallen onto them.

To avoid recurrence, try wiping them with a fungicide or neem oil. When watering again, avoid getting the leaves wet. Fungus loves water. So water the soil directly instead.

Causes of ZZ Plant Turning Brown – Fixed!

That explains the most common reasons why your ZZ plant is turning brown. As you can see, many solutions are simple fixes.

Your ZZ plant will make a wonderful living space companion for many years with a bit of TLC, not too much water (but not too little) and a proper pot! Be prepared to do the occasional wipe with a cloth and pure soap and water, and observe good care with humidity and sunshine.

For the most part, proper care should help to avoid any major problems. But don’t be too disheartened if your plant starts to show signs of stress. Just take a moment to go through the checklist above, identify the problem, and take the appropriate action.

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