ZZ Plants are often given the crown for one of the easiest to care for houseplants. However, this doesn’t mean they can adapt to every environment or are exempt from developing issues (we speak from experience!). It can happen that your ZZ Plant starts losing some leaves which is a sign that something isn’t wrong. Whilst some leaf drop can sometimes be natural, this is quite uncommon for ZZ Plants so it’s important to figure out what is causing the leaf loss.
In this post, we will uncover all of the different reasons why your ZZ Plant might be losing leaves. We will also be going over how to treat the issue and stop it from causing your plant to lose any more leaves!
Overwatering is a common cause of ZZ Plants losing leaves
If your ZZ Plant has started to lose leaves, then the first thing you should consider is overwatering. It is a common cause of a lot of houseplant issues as the issue can be pretty damaging. If the leaves that are falling off your ZZ Plant are dark in colour, or slightly softer than they should be, then your ZZ Plant might be suffering from too much water in the potting mix.
ZZ Plants really don’t like moisture in their potting mix and can very quickly start to rot in waterlogged soil. This starves your plant of nutrients and your ZZ Plant will have to shed leaves as it just can’t keep them alive.
To figure out if overwatering is the cause of the loss of leaves on your ZZ Plant, check the moisture levels in the soil immediately. If the soil is quite waterlogged and clumpy then replace it with fresh dry mix which will allow the plant to start to recover. Trim away the rotten roots and hold off on watering as much as you did before. Avoid waiting for the potting mix to dry out naturally as you are simply risking more damage being done over the next few days. Instead, by replacing the potting mix you’re allowing your ZZ Plant to begin the recovery process and it should stop them from losing any more leaves.
Top tip: remember to always use fresh potting mix as using soil from other plants increases the risk of carrying pests or diseases across your plant.
Moving forward, make sure to decrease either the frequency that you water your ZZ Plant or the amount of water you give it each time. By letting your plant’s soil dry out between waterings, it will reduce the risk of more leaves falling off your ZZ Plant.
It’s important to check the moisture levels in the soil before watering your ZZ Plant again. It’s not as easy as creating a schedule to water once every two weeks as environmental factors such as light levels and humidity mean that the soil will dry out at different rates across the year.
There are a few methods you can use to check the moisture levels in the potting mix to ensure you aren’t overwatering your ZZ Plant again in future, causing it to start losing leaves again.
Firstly, if your ZZ Plant is still fairly small and you can lift it no problem, then we recommend getting into the habit of lifting before and after watering. Over the next weeks, you’ll get a good understanding of how light your plant becomes when the potting mix is dry.
Another method to test the soil moisture is the finger or chopstick method. If the chopstick comes out clean, then the potting mix is dry. If there is still soil attached to the chopstick then wait a few days before watering your ZZ Plant.
The final method to test the moisture levels in the soil is to invest in a moisture meter. These literally tell you how damp or dry the soil is so you can accurately water your ZZ Plant and prevent any further issues such as your plant starting to lose leaves again.
If your ZZ Plant is losing leaves, it might also be due to underwatering
Funnily enough both over- and underwatering can lead to your ZZ Plant losing leaves, though underwatering won’t have that effect as quickly. It will take several months of improper watering before your ZZ Plant is forced to lose leaves due to a lack of moisture as they do prefer dry soil.
Here’s how to spot if your ZZ Plant is underwatered:
Leaves are dry and crispy
If the leaves that are falling off your ZZ Plant are dry and crispy to touch and look very dehydrated, then the problem is probably a consistent lack of water.
The potting mix is dry
An easy way to see if your ZZ Plant is losing leaves due to a lack of water is by taking the plant out of its pot and inspecting the potting mix. If the soil feels very dry to touch, almost like dust, then your plant needs more water.
When your ZZ Plant is underwatered, the foliage will sometimes turn light brown in colour. This tends to start off from the edges and moves inwards as the issue progresses.
Use a moisture meter
Just like with overwatering above, using a moisture meter will help figure out how dry the potting mix is and if you need to water more to stop your ZZ Plant from losing any more leaves.
How do I fix an underwatered ZZ Plant that is losing leaves?
Now that you’ve established that your ZZ Plant is losing leaves because of a lack of moisture in the soil, it’s important to solve the issue properly. The best way is to lightly water your plant once a day for a week. This will gradually increase the moisture levels in the pot. ZZ Plants won’t like it if their soil goes from bone dry to super soggy all at once. It can cause some environmental shock and this can actually mean your ZZ Plant starts losing even more leaves as a result. This is why watering very lightly once a day for a week will get your plant back on track.
Over-fertilisation can cause leaves to fall off your ZZ Plant
Most generic plant foods and fertilisers will recommend a dosage for your plants, but there is no way that this can be accurate for every individual plant. There are so many factors that play into how much fertiliser plants need and can handle; from size, age, light level, temperature and the list could go on.
Because of this, we always recommend starting with a fraction of the recommended amount and slowly increasing a little bit if your plant responds well.
ZZ Plants don’t need much fertiliser to thrive so the recommended amount on the bottles is often far too much for your ZZ Plant and can result in your plant losing leaves. Alongside leaf drop, too much fertiliser can also causes yellow or brown leaf tips/ edges so inspect the leaves that are falling off your ZZ Plant to see if you can spot these.
To solve the issue and prevent your plant from losing any more leaves, flush out the soil or replace the potting mix entirely. We recommend the latter if possible as it avoids any potential risk of root rot if the soil is being flushed through.
Then moving forward, to prevent the issue from happening again, stay away from fertiliser for about a year and gradually reintroduce it in very small quantities.
Remember that you don’t have to fertilise your ZZ Plant at all. You’ll see plenty of luscious growth without it (as long as your plant gets the right care) and you avoid the risk of your ZZ Plant losing leaves.
Those are the 3 main reasons why ZZ Plants lose their leaves. It’s important to look out for any other signs of unhappiness as these will also help you properly diagnose the issue. More often than not, leaf drop is accompanied by something else so keep a close eye on your plant. The sooner you are able to spot any issues, the easier it will be to solve them and get your plant back to full health. By giving your plant a good check each time you water, you’re able to spot any issues as they crop up rather than waiting until the problem has properly taken a grip of your plant before noticing.
Take a look through our ZZ Plant care guide for more information on how to keep your plant thriving.
Written by Billy Dawson