Monstera plants, also known as Swiss Cheese plants, have become very popular over the last few years and we can totally understand why. With their unique split leaves, they instantly become the focus of a room.
However, if your Monstera isn’t in its optical environment you may find that its leaves start to turn brown. The main reasons for your Monstera leaves turning brown are over- or underwatering, too much direct sunlight, dry air or a lack of nutrients.
Overwatering your Monstera can cause dark brown spots
If you notice that your Monstera is developing dark brown spots on its leaves, the most common cause of this is overwatering. We tend to go for a little and often approach towards watering with most of our houseplants, and this is especially the case with our Monsteras. They hate being sat in puddles of water, so you need to make sure that you have good drainage setup and don’t give them too much water at once.
Overwatering can very quickly lead to root rot which is extremely harmful. Alongside browning leaves, root rot can also cause the plant to become unstable and have trouble picking up nutrients through its root structure. If it isn’t caught quickly, it can mean your plant will not be able to survive for very long. If you think you might have overwatered your Monstera it’s important to check the soil right away and change it out completely if necessary.
Make sure to check the moisture in the soil before you water. The easiest way to check this is by digging your finger into the top two centimetres of the soil to see how damp it is. We also recommend picking up your Monstera before and after watering. This should give you a feel for when your Monstera might need a little more water, simply by giving them a lift and feeling the weight. However, we only recommend this if your Monstera is no bigger than 1/1.5 metre tall as they can get quite heavy quite quickly, so be careful!
If you aren’t really sure about how to know if your Monstera needs watering, we recommend picking up a moisture meter. They are super affordable and tell you how much moisture is in the soil.
Underwatering your Monstera causes light brown crispy edges
If you notice that your Monstera is developing light brown spots or dry crispy edges on the leaves, then it may be that you’re under-watering your plant. Although Monsteras don’t like sitting in water, they also don’t like their soil being too dry for longer periods of time. The easiest way to tell is again just by checking the moisture in the soil using a moisture meter and adjusting your watering schedule accordingly.
Your Monstera could be getting too much direct sunlight
If your leaves are turning brown, it may also be because your Monstera is getting too much direct sunlight. This can cause the leaves to burn, from which they will not be able to recover. Monsteras do like areas with bright light, but it needs to be indirect. South-facing windows can give your Monstera too much direct light so try moving them to a different window. You need to also watch out a little more in summer when the sun is a lot stronger for more of the day. It is best to move your Monstera a metre or so further away from the window in warmer months to avoid any leaf burn.
To figure out how much light your Monstera is getting throughout the day, you can use a light meter. It may be that your Monstera is getting a lot of direct sunlight in the morning, or is in too much shade in the afternoon.
Low humidity levels cause brown edges on Monstera leaves
Monsteras prefer a humid environment as they originate from tropical forests. If you find that the edges of your Monstera leaves are turning brown, then it may be because the air in your home is too dry for it. There are few really simple techniques to keep the humidity higher than normal for your Monstera; you can spray down the leaves with a mist bottle every few days, sit your plant in a tray with water and some pebbles or put your monstera in the bathroom and leave the shower on hot for 5 minutes.
The best way to consistently increase the humidity for your plant is by using a humidifier. They help to increase the water vapour in the air around your plants and will lead to a lot of happy and healthy plants which will keep the dry leaves away.
You can also pick up a good humidity monitor to keep track of everything if you’re more concerned. Make sure to also move your Monstera away from any air conditioning units as these create very dry air!
Lack of nutrients could be the cause
A less obvious cause of your monstera’s leaves turning brown is a lack of nutrients. If you haven’t repotted your monstera in new soil in a year or two it is definitely a good idea to swap out some of the soil in the pot with a good rich potting mix or compost. It is also a good idea to feed your plant every few months in the growing seasons (spring and summer) just to make sure is it getting enough nutrients to grow. You can either use a liquid fertiliser which you dilute into the water, or fertiliser spikes which you pop into the soil and nutrients are released over time.
These are the most common reasons why your monstera’s leaves may be turning brown. Once the leaf has started to turn brown there is often no going back for that leaf so we recommend pruning the dark parts of the leaf, or removing entirely if the whole leaf has turned brown.
If you catch the problem early and treat it appropriately your monstera should return to full health and begin to grow healthy luscious green leaves again!
Written by Joanna Turner